Amazon has Buy 1 Get 1 Free from select movies right now.
One deal of note is The Best Of Blu-Ray Vol. 1 and 2
Each costs $57 but has 4 movies
1. The Last Samurai
Phantom Of The Opera
The Road Warrior
If you buy both you only pay the $57 and get 8 movies which is a little over $7 a movie. Those movies are normally $20 alone.