if you are good with a solder iron you can make your own for well under the $250 range. A very common camera that is relatively cheap and easy to modify is the Sony S40. Read about building your own unit at Jesse's Hunting forum.

you can also find these homebrew, homemade cameras on ebay and in other forums but the prices are normally above your range for new units.

don't count out the other commercial models just because the memory doesn't match, holiday sales are on the way and flash cards will be goin on sale

hope this helps