games to buy for max of 4$ ?

Witcher 1 & 2

Child of Light

Chivalry

Fallout 3 , New Vegas

There is also a sale on tomb raider, it is 4.00$ now as well.

the evil within

Prison Architect, Witcher 2, Tomb Raider. I would take one of them. :P

Tomb Raider gives the most fun for a normal (easy to understand story, good gameplay) player IMO, but if you like economic games and you're not scared of early-access Prison Architect should be good choice. And also, The Witcher 1 and 2 <- their strongest side is story and the living world created by A. Sapkowski,.

any anouther games?

Arma 2: Combined Operations

Beyond Good and Evil

75% off on GetGames clicky (Edit: um, this might not be the Steam version, dang)

BattleBlock Theater