Library - haven't been to the library for years? It might be time to "check it out" (pun intended). You can borrow any available DVD's, usually 2 at a time.
Hulu.com - I watch my favorite TV shows on Hulu. They also have great movies you can watch for free. Upgrade to HuluPlus for more movie selections.
Local Movie Nights - There are often organized movie nights in certain neighborhoods. Check your local newspapers or check online for one near you.
Swap or Borrow - I'm sure you have DVD's stored away that a friend might want to watch. See what they have, you may be able to swap or borrow a few from them.
Crackle.com - This site is similar to Hulu.com - they offer a pretty good selection of free movies and television shows.
Redbox.com - For only $1.20 per movie, you can rent most of the latest "just released" DVD titles. Check online for discount promo codes. May sure to return each DVD the next day to avoid paying late fees.