I bought a Harbor Freight laser thermometer a few years back - works fine for me. Seems like I paid about $30 for it. I use it in the lab when doing experiments that involve heat to tell me if something is cooled enough for me to touch it or if the chemical reaction is finished or whatever.
I worked on various types of IR systems for the military when I was a consultant doing all things wild and esoteric like image signal processing and I can verify with Carl - IR is a waste of time as a treasure hunting tool.
Save your money and buy a good metal detector
or if you can dowse get a couple of coat hangers.
Goldfinder