Those Fools over at Motley Fool have come up with 50 tips for saving money. Here's an excerpt:

1. Eliminate unnecessary fees
9. Turn off the lights when you're not using them
14. Ask your utility companies to perform energy audits (they'll do it for free)
24. Make your credit card work for you
31. Grocery shop on a full stomach

These are just a few. The entire list can be found here.*

* Requires registration, which is free. Or try bugmenot.