Haven't seen ODST this cheap since I started actually looking for it. $6 at Target on clearence means it never happened near me. The Targets in my area NEVER have anything on clearence and if they do it's Dora the Explorer or some other worthless garbage.
I also believe Reach is the best Halo game. Easily looks the best, has the best gameplay, and the best MP. The story was probably better in 3, but I still liked the Reach experience the best.