You will want to have at least $600-1100 ready to spend if you want to get into airsoft and get all the stuff you'll need.
Airsoft isn't for those that can't afford it. (Or stick with it for the matter.)
Bout the only crap that may suit your needs is CYMA brand AEG's. They are, as previously stated, CRAP.
May I ask your age & how much you are willing to spend to get into the sport?
You say you want to shoot cans, Then go to Canadian tire and purchase a Crossman BB gun. Will perform a LOT better then an airsoft gun for that purpose.