I just signed up for a two week trial at www.lovefilm.com. For the next two weeks, I can rent unlimited dvds. At the end of the two weeks, I am going to do the same thing with a different company. And again after that. I figure I can get a few months free dvds out of it. Plus, you can get cool stuff that you might not be able to get in a regular rental store (the chain in Belfast doesn't rent tv series.)
And so I don't sound completely cheap (and there's a difference between being cheap and broke!), if I like one of the services I would seriously consider joining.
Note the freeness depends on remembering to cancel your trial membership!