My Unbalanced Washer, please help with advice?

I have a Whirlpool Cabrio, and it keeps unbalancing itself, no matter what the load in the washer is. I can't even wash one pair of coveralls (Nomex) without it being off balance. Is there a way to tighten up the drum so that it doesn't rattle out of control? (I'm not very rich at the moment, or else I'd call a service man to come check it out.)