I picked up my copy of LOST season 4. Have you got yours? LOST Season 4 is $36.99 on Amazon. I picked up my copy at Best Buy for $37.99. They were also offering $20 off a previous season if you purchased Season 1 - 3. I stopped in Target and they were offering something similar, they offered a $20 gift card if you purchased Season and a copy of one of the first three seasons.
There are a lot of extras on the DVD, that I have not been able to check out just yet.