Today I am returning Heavy Rain to game stop(pre-owned)

They said you can return it after 7 days and get a refund.

I just don't know what game I should get,how much is Mass Effect 2 pre-owned?

Its not really worth buying used from Gamestop IMO. Its only ever $5 cheaper to buy used than new in most cases. If I buy used I look on Kijiji/Craigslist or local pawn shops. 

haha thats what i used to do. The old buy and return trick. your better off getting gamefly though, and you should try killzone 3. Mass effect 2 is too long to beat in a week.

Good luck on finishing ME2 in a week.

Go BUY Two Worlds 2 instead.

"haha thats what i used to do. The old buy and return trick. your better off getting gamefly though, and you should try killzone 3. Mass effect 2 is too long to beat in a week."

I agree.  especially if you have the Move!  

I'm not going to beat Mass Effect 2 in a week.

I'm going to return Heavy Rain,but I should try mass effect 2 in a week.

Yeah buy Two Worlds 2 instead.

It needs more buyers with those 2 million copies shipped.

Mass Effect 2 took me 22 hours with over 800GS, plenty of time.

? they shipped 2 mil?

Definately try out Mass Effect 2 and at most it will take 30 hours to beat so dont worry. A week is plenty