Unfortunately, you're a couple weeks too late. Your best bet is to wait a bit and see when retailers are going to bail on HD-DVD and blow out the discs.
Same as bob330i says, just wait for the blowout sales to really rack up.
For a quicker buy, I suggest Amazon. $13.75 used / $15.29 new. I believe it is still in the neighborhood of $24-29 at Wal-Mart, but the HPs 1-4 have appeared lately for 19.00 each.
