This isn't exactly a freebie, but it's only a small donation. If you donate $2, you can pick out a family favorite from Blockbuster to rent for free. I haven't read up too much on it but I'll provide all the links. Offer ends September 1.
http://www.blockbuster.com/bb/article/details/0,7413,ART-711,00.html
I just got this, before reading it here, at Blockbusters. You recieve one "free" VHS rental everyday after donating a one-time "fee" of $2. I got Mr. Bean's Rat Race. One new VHS rental everynight, it just can't be a movie off the wall. Meaning, it has to be atleast a year old. IMO still a good deal though.