I happened by Harbor Frieight today in Crestwood. They have a three day sale right now that includes an infrared thermometer. I forget what the original price was, but I think it was in the $70 range. But they have them as part of their sale for $19.99.
I haven't verified how accurate they are yet. But I am making a yeast starter right now, and so far, every time I've used it on that, the temperatures are right where I would expect them to be. I'm thinking that if this is a fairly accurate thermometer, I should be able to use it to get instant readings on my hot water and mash temperatures.