If I understand your question correctly, I think your best bet is signing up for Blockbuster Total Access. There are a few plans and with all the Blockbuster Total Access plans, you can return DVDs by mail or exchange them for free movie rentals or discounted game rentals at your local, participating Blockbuster store. So not only are you getting an unlimited amount of movie rentals for the month for a flat low fee, but you also can return a movie you received in the mail to a local store and still get that "movie-store experience."
You can get a free trial and see how it works out for you. If you don't like it, you can cancel the membership at no charge.