Yeah we got all 3 of ours from Wal-mart as well. I believe ours was around the outside lighting section. Very small section that could easily be missed unless you are looking for it.

Edit: here is a link to the one we got from Wal-Mart for $15 or 14.99 or something like it.

http://www.natlallergy.com/allergy/p...ermometer.html