After several bad experiences with Blockbuster's "No Late Fees!" policy (translation: we'll sock you for the whole cost of the movie if we feel like it), I signed up for Netflix. In case you've been living under a rock or in Communist China and aren't familiar with the Netflix service, you sign up to receive DVDs mailed to you as often as you like. Pricing runs from $9.99/month for 1 DVD at a time, as many as you like per month, to $17.99 for 3 DVDs at a time. Netflix pays all shipping costs.
After evaluating how much I want to spend on movies each month, I signed up for the $11.99 plan. I get two movies at a time, exchanged whenever I want, but with a maximum of 4 movies mailed to me in any given month. At first I thought 4 wouldn't be enough, but I realize there's usually about a 4-8 day gap between when I finish watching something and when I actually return it (hence my problems with Blockbuster), so the restriction hasn't caused me to have any delays yet.
My first priority was TV shows. The Simpsons Season 5 and Firefly were my "tests." Netflix shipped the first disc from both series the day after I signed up, and I received them two days later. The envelope is reusable - pull the front flap off (that had my address on it), and inside is a second flap with the return information and a "no postage necessary" stamp. It worried me a bit that a DVD would crack or something, since the envelope doesn't offer much support, but I suspect that (actual price of a physical DVD) x (% chance the DVD will break) < (cost of sturdier packaging). I've had no issues with scratched or broken discs yet.