Another noob question

You'll get CD-Keys.

You will get three keys or possibly only one key which when activated will give you two copies in your inventory, depends on what the game is.

If it's a 3 pack you get 3 individual keys. You can't buy game for your inventory outside of Steam.

where is it on sale? on gmg for me its normal price

i suggest wait for the winter sale.
when the winter sale comes the game will cost 3.74$ on steam and the four pack something like 7.49$.
so my suggestion is wait for the winter sale and get it cheaper and tradeable instead of poor keys.
:)