wait what exactly is this
Alright. So long story short, there's a game called Counter-Strike: Global Offensive, or CS:GO for short.
CS:GO has a case system much like TF2's where you can buy keys and unlock crates to get random skins for weapons, and this program basically mimics the picking process for how you get skins in CS:GO.
While there are different tiers of skins, a Consumer-grade (lowest) can look just as good as a Covert (highest non-knife) if you put your mind to it.
Of course, since your trying to go for skins based on how much money they're worth on the market (or for betting) and not for how they look, most people try to go for the Classified skins or higher, since most of them go on the market for more than the key they bought, making their key worth it.
Stattrak's are things that come up as well, being basically kill-trackers. These can jack up the prices of even the stufftiest skins, and have about the a low chance of appearing. God help you if you find a Stattrak knife skin. Phishing bots up. The. Ass.
Now here are the different tiers.
Blue: Mil-Spec, Which is essentially a wasted key x10 (unless you somehow manage to randomly find an AK-47 Black Laminate from a random game, as these sadly do not drop from crates and go on the market for lodsofemone). unless you get a Factory New (highest quality) Stattrak, you probably won't be getting your money back.
Purple: Restricted, believe it or not, is also a wasted key, but much less so. Even though they are a lot rarer than the blues, they usually go on the market from about $0.50+, and unless yo are lucky enough to find a Stattrak Factory-New skin, you're stuff out of luck.
Pink: Classified skins are basically where things start getting good. Most of the Classified skins go for at least the price of one key at the lowest quality, and
$100s at the highest (with Stattraks added in there somewhere).
Red: Covert, this is where things get really hot. Covert skins are usually reserved for all the fan favorites, such as M4s, AWPs, and AK-47s, but there are covert skins for less-favored weapons. The cheapest Coverts go for about the same price as a key, but these are usually for weapons like the AUG or Sawed-Off; basically worthless in the eyes of many. The GOOD (subjective) Coverts all belong to the above mentioned 3 weapons, and they go for
$100s as well. But, the last 2 are nothing compared to...
Gold (not yellow, you scrub): Covert Knives, these are what you open crates for. These knives are 10x more expensive than any of their in real life counterparts, if just because they are so loving rare. Your chance of getting one of these is one-in-a-million. You might be asking yourself "What's the cheapest knife on the market right now?" and that would be the Gut-Knife| Safari Mesh, but it still goes for about $43. The most expensive knife?
A whole forgetload of them, all for $400! Getting a knife skin is considered a great achievement in and of itself. Your friends will envy you, phishing bots will adore you, the Brazilians will watch you with hateful scorn. Getting a knife is the ultimate CS:GO achievement (besides winning Dreamhack, maybe).
The case simulator is just there to make you afraid of opening cases, and now you know what this is.
