What are csgo keys ?

Title says it all

 

Valve introduced "Cases" a few years back in CSGO. These "cases" are basically weapon containers. Each case contains a different set of skins for certain weapons. Each kind of case has a unique key that it requires in order to extract the containing weapon skin from it. Example, CSGO Weapon Case 3 can ONLY be opened using a CSGO Weapon Case Key. Similarly, Operation Vanguard Case can only be opened using an Operation Vanguard Case Key.
These keys can be bought directly from valve @ $2.49 per key, OR they can be purchased through the steam community market which is usually a little expensive most of the times. You may obtain one through trading with players as well.
Keys are not dropped at the end of map.
I suppose thats all there is to know about keys

 

Pretty much what Designer said but some people would use keys to pay for things instead of money. So lets say a skin was $75 and you wanted to purchase it with keys. Since each key is $2.49 it would be about 31-32 keys.

 

Exactly what designer said and moses, buying keys allow you to open cases and you can get loads of things from cases.

 

CSGO keys buy cases and u can get random guns out of cases