Hi Digimon Tamers, I'm a tamer from Barbamon Server and i decided to give some guide about how to make money in Digimon Masters Online.
Especially in newly-born Omegamon Server where the price is still fresh and many people started playing again.
Some new players that play this game for the first time don't know what item should they sell and keep, so i will share what i know about this game.

NB : I have played this game from 2012 and stopped in 2014, i just came back again 3 months ago and found out that there are bunch of new items and digimons.
My Barbamon Nick is : PrinceLovett
My Omegamon Nick is : Lovett

Every MMO has its own currency. Digimon Masters Online's currency is group by three symbols.

Tera = 1 Tera = 1000 Mega
Mega = 1 Mega = 1000 Bit
Bit

You can see your money in you Inventory by Pressing "I" key or click on Inventory Icon at the bottom UI.

First of all, the basic income from the game is drops from monsters you killed. They will drop some items that usually contain :

1. Coins
   Every monster you killed will drop shiny gold coin that have different amount for every kind of monsters you killed.
   
   
2. Digiegg (For Return) / Cracked Digiegg
   An item that looks like a broken egg, you can return that thing to get some money. There are 7 ranks of them :
   
   • Rank 1 Cracked Digiegg (25 B each) : Yokohama, Western Village, Silver Lake
     
   • Rank 2 Cracked Digiegg (100 B each) : Digimon Farm, Oil Refinery 3, Silver Lake
     
   • Rank 3 Cracked Digiegg (150 B each) : Silver Lake, Western West
     
   • Rank 4 Cracked Digiegg (200 B each) : Silver Lake, Silent Forest
     
   • Rank 5 Cracked Digiegg (250 B each) : Dark Tower Wasteland, Silent Forest
     
   • Rank 6 Cracked Digiegg (300 B each) : DTerminal B2 Dungeon, Lost Historic Site
     
   • Rank 7 Cracked Digiegg (450 B each) : Maze Entrance, File Island Waterfront, Server Continent
   
   
3. DATA Digiegg
   This digiegg depends on the kinds of monsters you killed. There are 9 kinds of this eggs
   
   You can scan DATA Digiegg to obtain the LOW-Class Data and sell them to other players for money.
   Here is the price rank for Data (first rank is the most valuable) :
   
   • Aquatic
     
   • Dragon (You can get 2 low class Data when scanning Dragon DATA Digiegg)
     
   • Bird
     
   • Beast
     
   • Plant
     
   • Devil
     
   • Fire
     
   • Insect
     
   • Rock

There are some items that can sell for some good money.

1. Digicore
   It's an item that looks like this :
   
   This thing can be sold for good money depend on the Event that are being held by the game.
   You can obtain it by scanning any Mercenary Digiegg.
   
   
2. Monster Card
   There are items called Monster Card from level 1 to level 7.
   
   • Monster Card Lv 1 contains Fried Potato and Low-Chance of Evoluter.
     
     
   • Monster Card Lv 2 has high chance to drop Elecmon / Gabumon Mercenary Digiegg / Beast DATA Digiegg and can be used to farm Beast DATA.
     
     
   • Monster Card Lv 3 contains Hamburger and Evoluter.
     
     
   • Monster Card Lv 4 contains Hamburger and Evoluter.
     
     
   • Monster Card Lv 5 contains 3 Digicores if it is dropped from the monsters. You can farm this card in Dark Tower Wasteland and File Island Waterfront (CannonBeemon,Waspmon,Crowmon). This card can be expensive if there's event using Digicore (Character Bound) as main thing to trade.
     
     
   • Monster Card Lv 6 has good source to farm Chicken Combo (Consumable Items) but the popularity is down right now. It drops in Digimon Maze Area and File Island Waterfront.
     
     
   • Monster Card Lv 7 has high chance to drop Evoluter (Items to expand evolution slot of Mercenary Digimon) and can be obtained only in Infinite Mountain Dungeon.
     
     Thank you Russel Coight for the Evoluter comment.
   
   
3. Chicken Combo
   There will be many players searching for this Consumable in this new server. You can farm this at File Island Raids (Kuwagamon, Meramon, Ogremon, Leomon, Monochromon).

I will give the list of the Cash Item using Premium Currency (Crown) that can be sell for good in-game money and have super popularity in game.

1. Digimon > Evolution Item
   The popular and demanding Evolution Items in this game are :
   
   • Bokomon Book Of Knowledege
     This item is required to summon Spirit Digimon. Players that want to make KaiserGreymon or MagnaGarurumon (2 Strong Digimons) will need 20 Books. So this thing will be the most popular Evolution Item in game right now.
     
     
   • Toy Gun
     This item expand the Burst Mode Evolution for Impmon. This Digimon has the highest DPS in game because of his fast Attack Speed.
     
     
   • Omega Blade
     This item expand the Burst Mode Evolution for Veemon (X-Veemon Line). X-veemon Mega Form (Imperialdramon Dragon Mode) also have fast Attack Speed like impmon, but his Burst Mode Attack Speed is slower than Impmon's Burst Mode.
     
     
   • Return Of Nothingness
     This item expand the Super Burst Mode (Apocalymon) for 4 Mercenary Digimon (Betamon, Woodmon, Soulmon and Mechanorimon). Apocalymon is Attribute and has 3 skills where the third skill is AOE skill so it's good for farming items in tight spot weak monsters.
     
     
   • Code In Alpha
     This item unlocks the Riding Mode of Alphamon Ouryuuken Mode(Jogress).
     
     
   • Behemoth
     This item unlocks the Riding Mode of Beelzemon (Impmon). Who doesn't want cool bike in game ?
     
     
   • Black Tentacle
     This item expand the Burst Mode Evolution for Keramon because its Burst Mode (Armagedemon) is UK Attribute (Strong against all Attribute) CMIIW.
     
     
   • Mode Selector
     This item unlocks the RIding Mode for some Mega Digimons. Some digimons need more than 2 ModeSelectors to unlocks its riding mode.
   
   
2. Expansion
   
   • Digimon Archive Expansion
     This item unlocks the 1 slot in Digimon Archive so player can obtained more Mercenaries for their collection.
     
     
   • Inventory Expansion
     This item unlocks the 1 slot in Player Inventory so player can obtained more spaces while farming.
     
     
   • Warehouse Expansion
     This item unlocks the 1 slot in Player Warehouse so player can save more things in their warehouse. But this thing is not too popular because we can store our items to other character in the same server using shared warehouse (14 slots at the bottom of warehouse).
   
   
3. Avatar
   
   • Option Change Stone
     This item is popular in all server except Omegamon because Omegamon is sill new and there's still no high tier accesories yet.
     
     
   • Costume
     People will buy Costume to get another buff so they can easily progress in game.
   
   
4. CURRENTLY OMEGAMON SERVER DEMAND
   
   • Z'DHou
     This item expand the Burst Mode Evolution for Gabumon.
     
     
   • DramonBraker
     This item expand the Burst Mode Evolution for Agumon(Classis).
   Why both of these items are on high demand in Omegamon Server ?
   When tamer in Omegamon Server reached lv 50, they will Get Reinforced Lv 5 Jogress Digiegg, and many people will get Gabumon / Agumon (Classic) but can't reach their Jogress. WHY?
   Because Jogress Quest for Omegamon is located in Digimon Maze F3 and it took times to go there (Bunch of quests).
   These items will be demanded for this month in Omegamon Server.

(#Unfinished Section) Here i will explain about Chipset. You can get Chipset Lv 6 by scanning Super Class Digiegg (Blue Border) and Chipset Digiegg. These things dropped in Digimon Maze Area (Maze Entrance - Maze F3). You can also get Attribute Rank D by scanning that Rank 7 Super Class Digiegg.

1. Chipset Source
   
   • Rank 7 Super Class Digiegg
     
     
     
   • Chipset Digiegg
     
     This thing can be returned for 6 each or can be scanned to obtain Lv7 Chipset. They are easily drop in Digimon Maze F1-F3.
     
     
   • Chipset from Rank 7 Super Class Beast Digiegg
     
     Chipset AT Lv 6 is ranged between 60-80 AT (I Forgot about this).
     
     
   • HP Attribute D from Rank 7 Super Class Beast Digiegg
     
   
   
2. Digimon Family
   There are 10 Digimon Families. Every form are different each other, so Mega Form sometimes has different Family with its Rookie Form. They are known as :
   
   Family

   Digiegg

   Chipset

   Name

   

   

   ***

   DA = Dark Area

   

   

   

   DS = Deep Savers

   

   

   ***

   DR =Dragon's Roar

   

   

   ***

   JT = Jungle Troopers

   

   

   

   ME = Metal Empire

   

   

   

   NSp = Nature Spirits

   

   

   

   NSo = Nightmare Soldiers

   

   

   

   UK = Unknown

   

   

   

   VB = Virus Busters

   

   

   

   WG = Wind Guardians
   
   
3. How to get Chipset All Family Lv 9 ???
   This Chipset can be obtained only in Holy Beast Dungeon in D-Terminal (Guilmon NPC).
   - Xuanwumon Dungeon (Crystal Scar)
   - Zhuqiaomon Dungeon (Will Of Flame)
   - Baihumon Dungeon (Traces Of Black Steel)
   
   You can also obtained valuable Items like (I'll add the pictures later) :
   
   • Jump Booster [All Area]
     
   • Evoluter
     
   • Fruit Of The Goddess
     
   • HP DS AT DE Chipset Lv 9
     
   • Ring, Necklace and Earring (Accessories for Tamer)
     
   • Shiny Ring, Shiny Necklace and Shiny Earring (Max Stats Accessories for Tamer)
     
   • Shiny Clothes, Shiny Pants, Shiny Gloves (Bonus Stats Equipment for Tamer).
     
   • Attribute Booster
     
   • High-Tier Consumables
     
   • 2 Hours Buff Items (Exp 1000%, HP 50%, DS 50%, AT 50%)

This section shows you the spot to farm certain DATA you need. Note that this is for fast DATA farming, because they are weak, fast spawn, and spawn in tight spot.

1. Silver Lake (File Island Area)
   
   • Beast DATA
     Best spot to farm this DATA is at Elecmon and Patamon.
     
     
   • Insectoid DATA
     Best spot to farm this DATA is at Kunemon and Dokunemon.
     
     
   • Plant DATA
     Best spot to farm this DATA is at Mushroommon, Lilimon and Woodmon.
     
     
   • Rock DATA
     Best spot to farm this DATA is at Gotsumon.
     
     
   • Dragon DATA
     Best spot to farm this DATA is at Koromon. Please remember that Dragon is the only DATA you can get 2 pcs when scanning the DATA DigiEgg, so it's a nice income too.
     
     
   • Aquatic DATA
     Best spot to farm this DATA is at Betamon or Seadramon.
     
     
   • Bird DATA
     Best spot to farm this DATA is at Birdramon and Sabirdramon (But they spawn slower than other mobs).
     
     
   • Fire DATA
     Best spot to farm this DATA is at Demimeramon and Candlemon. You can also get easy Chicken Combo because their spot is nearby to Kuwagamon Raid.
   
   
2. Silent Forest (File Island Area)
   
   • Devil DATA
     Best spot to farm this DATA is at Ogremon or Bakemon (Ogremon spot is better because it is nearby to Ogremon Raid so you can farm Chicken Combo too).
     
     
   • Fire DATA
     Best spot to farm this DATA is at Meramon.

These things will ONLY drop in File Island Area with super low chance and expensive price to sell. Hope you guys got and sell them easily.

1. Tamer Exchange (Tai)
   
   
   
2. Tamer Exchange (Matt)
   
   
   
3. Tamer Exchange (T.K.)
   
   
   
4. Tamer Exchange (Mimi)
   

These are the Good Ongoing Events in Digimon Masters Online in 2 weeks.
Duration : 29 November 2016 - 13 December 2016

1. VIRUS Digimon Buff :
   Period : Nov 29th, 2016 (after server MT) – Dec 13th, 2016 (before server MT)
   Details :
   - To celebrate BlackSeraphimon’s Riding Mode update, abilities of a few
   Virus-type Mega-form Digimons will increase during the event period.
   - Normal AT +50%, Skill Damage +100%, Normal Defense +100%, HP +100%
   
   - Beelzemon (includes Burst Mode)- Apocalymon (includes Pinochimon, Piedmon, MetalSeadramon, Mugendramon)- Diaboromon (includes Armagemon)- BlackSeraphimon- Arkadimon (Mega)- Death-X-DORUgoramon (includes Death-X-mon)- Gulfmon
   • Event Items.
     Period : Nov 29th, 2016 (after server MT) – Dec 13th, 2016 (before server MT)
     Details :
     - To celebrate BlackSeraphimon’s Riding Mode update, Virus-type DigiEggs
     will be available for production
     - During the event period, you may exchange [Virus Cell] items to various items
     via Digitamamon (Item Production) NPC at DATS Center.
     - [Virus Cell] items will drop at a random chance when defeating enemies on field.
     [Item Productions]
     - 1 Reinforced Mercenary DigiEgg (Event) - Impmon *1 EA for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Keramon for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Arkadimon for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Dorumon [Death-X-DORUgamon] for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Palmon [Woodmon] for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Gazimon for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Tanemon for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - Hagurumon [Mechanorimon] for [Virus Cell] 300 EA
     - 1 Reinforced Mercenary DigiEgg (Event) - DemiDevimon [Soulmon] for [Virus Cell] 300 EA
   [/olist]

There are some tips i can share for you :

1. Digicore can be obtained easily in Cherubimon Spot (File Island Waterfront). You can either return the egg for 1 each.
   
   
2. Digmon Boss (Western Village) and Piyomon Boss (Wilderness Area) will always drop Monster Card 2.
   
   
3. You can easily get Chicken Combo from Raids in File Island Map (Kuwagamon, Meramon, Ogremon, Leomon, Monochromon).
   
   
4. If you killed Monsters that weak against your Digimon Attribute, your attribute experience will go up. But not in DA Attribute digimon, you can only raise DA Attribute by returning Cracked Digiegg using your DA Type Digimon. (Ex. Gabumon, Renamon, etc)
   
   
5. Leveling can be a good source of money too if you keep leveling from lv 73 in Argomon/PileVolcamon/GranKuwagamon Area in File Island Waterfront.
   
   
6. Cerberumon in Digimon Maze Entrance drop Decent Beast DATA and some Chipset Digieggs to return for 6 each.
   
   
7. You should open your Inventory Expansion to make your farming longer and have more space to carry the loots. It's still cheap in Omegamon Server right now, so grab it.
   
   
8. If you already reach Tamer Lv 55, You can farm money easily in Digimon Maze Entrance, the Coin is 400 each and most of the drops are Rank 7 Digiegg + Chipset Digiegg. They can be returned for a good sum of Money.
   
   
9. Do the Daily Quest in File Island Waterfront (Trio Mono Quest) because it gives you 10 Green Clovers (Worth 5 Million Exp for Digimon Lv 60-90 (Thank you Chris Rock) and 100 . (Thank you Fabu Dodo)

I still not finished this Guide yet. If you have some things to share here, feel free to comment this guide and i will add your tips in this guide.
Please this guide if you find it useful,
Thank you and Happy Playing.