I got this one from Amazon. I actually got it for $9 but they have gone up just a tad to $16. I got this one because it takes a regular 9volt battery and not some expensive specialty battery. It has been awesome for me and I have had it a couple years now. It also has a built in laser that is tons of fun for my bulldog to chase.

http://www.amazon.com/HDE-Accuracy-N...ds=ir+temp+gun