The Spot-Check through Cutler Supply is $21.95 and an extra pack of 4 batteries for it is $3 or so. Stromberg's hatchery sells the same one for over $30.
Any one with an actual accuracy rating (which you will not find on the household thermometers, only a range of low to high temps) should do well. There are some very, very expensive ones, but this one is probably the best for the money I've seen.
Any one with an actual accuracy rating (which you will not find on the household thermometers, only a range of low to high temps) should do well. There are some very, very expensive ones, but this one is probably the best for the money I've seen.