i posted this for cornsnakefreak earlier, but it describes how i made my incubator
i build my own incubator in the summer out of a 13 dollar athletic cooler. I used a sterlite container for the egg box with 2 small holes drilled on either side to regulate humidity. The summer was really hot, so the cooler kept the eggs at a great 80-82 degrees. for the spring breeders i put some heat tape at the bottom of the cage, and ran the cord through the spout for water. then put two bricks on either side of the tape, and set the egg box on that. Also have 2 thermometers, one in the incubator, and one in the egg box, same with the humidity readers. TEST everything out before the eggs come. I suggest you run the incubator for a few days to see how the levels get, and make adjustments from there. Besure to fan the eggs every 3-4 days too with the egg box lid, to circulate some fresh air. Terry Dunham from albino tricolors gave me that tip.