you have to do your own research on which titles work, but with certain combinations of hd dvds and blu-rays, if you buy 3, you get one of them free.
this is what i've purchased thus far:
round one - hd dvd: terminator 3, TMNT and batman begins. $47.90 shipped
round two - blu-ray: apocalypto, pirates of the caribbean 1 and 2. $47.90 shipped
round three - blu-ray: the fifth element (remastered), terminator 1 and 2. $39.90 shipped
free shipping on all orders of $25 and up.;)