[H] cards [W] games that i dont have

For you 5 Black Ops II cards?

Well, that depends on the card value on market

Let's say:

Blackguards - 12 cards 0,1 each (basically half of one TF2/CS:GO key)
Legend or Grimrock - 10 cards 0,1 each
Orcs Must Die - 8 cards 0,1 each
Legend of Dungeon - 5 cards 0,1 each

As for Grid and Shadow Warrior, it will be too many cards ;)

EDIT: If you want to take all 4 games I can go down from 35 cards 0.1 each to 30/0.1 each