Right now, there are only 3 cases containing chroma knives, one of them (Chroma 3 Case) is still really expensive at the moment. Due to the fact, that people opening cases hope to get one of those, Chroma and Chroma 2 cases are really popular.

The only reason, why they are really low at price, is that the new Chroma 3 case is even more popular. But since Valve has added a new case (Gamma Case) to the game already, it will be outdated within a few weeks.
You can find more about that point in the next paragraph.

Additionally it's the best opportunity to buy Chroma/Chroma 2 cases now! At their current price (~6 cents) you can buy so many cases and even if the price will only rise by a few cents, you will make some decent profit still! I'm gonna go into detail on that later.

Furthermore Chroma/Chroma 2 Cases are no longer a common drop and the supply is decreasing day after day. We have already seen this price development more than once. Weapon Case 1, Weapon Case 2, Weapon Case 3, Bravo Case, Huntsman Case, Vanguard Case... and now the Chroma and Chroma 2 Case.

Long story short: There are many reasons why the price of Chroma/Chroma 2 Cases will rise in near future and it can't decrease much more. So it's an risk-free investment with a high potential to make a lot of money for you to buy a knife!

As mentioned in paragraph 1 the price of Chroma and Chroma 2 cases dropped after the release of the Chroma 3 Case.

Pay attention to the steady price of Chroma 2 Cases (image above) and how the price decreased rapidly after the 28th of April, the release date of the Chroma 3 Case (lower image).

Of course a new case is more popular than older ones, so Chroma/Chroma 2 Cases have been sold less (before release: 80.000 per hour; today: 5.000 per hour) and their price has dropped by a good amount!
But after a while Chroma 3 cases will also fall in price, because their amount is increasing. In this way it is getting less popular, so they will sell at a lower rate, thus causing Chroma/Chroma 2 Cases to cost more in a few weeks.

So, let's say you buy 100 Chroma 2 Cases at their current price of ~6 cents and it rises back to a price just as high as before the release of the Chroma 3 Case (and this will happen in a few weeks as mentioned above), meaning it will sell at around 18 cents, you will win more than $9 by investing only $6! That's 150% profit!

Investment: $0.06*100=$6.00
Outcome: ($0.18-15%*$0.18)*100=$15.00
Profit: $9

So just imagine, if you invest $40, you will get 100$ out of it (60$ profit)!

At this rate, your dream of a knife will become reality in no time at all!

I hope that I was able to show you an easy and safe way to make money. I also have invested around $80 in Chroma and Chroma 2 Cases already (so my inventory is completely filled up with them :*) ) and if you ask me, which case you should buy by now, I would suggest to invest in Chroma 2 Cases, because they have been/are more popular than the original Chroma Case.

At this point, I'd like to thank you for reading my guide and if you have any questions or remarks please do not hesitate to write them down in the comments.