Just add the bot http://steamcommunity.com/id/fzcardkeysbot/as a friend and use next commands:

Buying Cards

!buy [amount of keys] : In order to buy sets for an X amount of keys.

!level [desired level] : Calculates how many sets and keys it takes to reach a certain level (doesn't go above 1000).

!check : Checks how many sets you can buy.

!check [amount of keys] : This command checks how many sets you can get by the amount.

You get:

16 complete trading card sets for 1 CSGO key

Bot always checks your previously crafted badges so you get sets you need only

Just add the bot ^_^: