Is it bad to buy a mouse or hamster from Petco/Petsmart...?

I know a lot of their animals come from breeding mills. But there are very few hamster/mouse shelters in my area.. and the closest one wants twenty bucks for a mouse. At Petsmart they sell them for three dollars... The Petsmart nearest to me takes good care of their animals (especially their fish, which surprised me, considering pet stores usually have the filthiest tanks). Is it okay to buy a mouse or hamster from Petsmart? If so, which would you choose to buy? I heard mice are friendlier? And I like being different so I might get the mouse.. haha. Everyone has hamsters! If I keep it in a 10g aquarium will it stink up my bedroom? Thanks everyone!