Or you can go even cheaper and get ya a foam cooler, a foot or two of flexwatt, and your thermostat. Will work just as good for just a few clutches, it's what I used for my first few years. Wrap the flexwatt around the sides and tape in place, set a dish of water in the bottom, and stack the egg boxes either on top of the water dish or on top of a grate thats over the water dish depending on how big of a cooler you use. Total cost will be about 20$I also miss the humidity containment my old foam ghetto incubators held.......I rarely had to ever add water to the substrate in my "coolerbators" other than keeping the water dish full. In my fancy big cool kid incubator I have to almost always add some in the last few weeks.