Amazon steam games.

Maybe you should wait for a good sale there, and then buy something, a Steam redeemable game would be good.

Wait for sales :D

It's games. Plural.
'Game's' is a contraction, instead of typing 'game is,' or in modern changes here in the US is now allowed to be used as the possessive.
In other words you're saying the game either is something, or owns something, and then not saying what, because you don't mean to do either of those two things. You're trying to use the plural, which has no apostrophe. Just 'games.' The end.

And now that I'm over the annoyance of a grammatical pet peeve... As the other people have said, wait for a good sale. And yes, there's a place on amazon that shows games on sale, and gives you the option to limit results to Steam DRM. Like this.