EDIT: These Sam's Club offers get Hiffed awfully fast, don't they?
These free Glad ForceFlex trash bags from Sam's Club are fantastic at not breaking while you stuff them full of all the dirty dishes your roommate left in the sink. The bags even mask the smell long enough for you to carry them into his room and scatter said dishes all over the floor!
Or I guess you could just put trash in them. Whatever floats your boat.
As usual, you don't have to be a Sam's Club member in order to get their freebies.