After reading a bunch of 'recipes' on the Internet for DIY 'bators, I decided to try my hand at one. First, I hit the local dollar store for: a styrofoam cooler, a picture frame (for the glass), 2 heavy ornamental 'rocks' for heat sinks, a wire bar-b-q griller, and a sponge. Total cost: $6 + tax. I already had duct tape and a thermometer/hygrometer. I calibrated the thermometer using the crushed ice/water method and found it read 32.5 degrees so it was only .5 degrees off -- an amount I could live with. Then I cut a hole in the lid of the cooler and installed the glass pane: Hint: I angled the cuts on the edges a bit so the glass had something to rest on & didn't just fall through. Then I borrowed an old trouble light from my neighbor, cut a hole for it in the bottom of the cooler, and then taped it in. I tore apart the grill I had bought (it was 2 pieces of wire grill) and cut a slit completely through one side of the cooler and 1/2 way through the other side so I could insert the grill as a shelf for the eggs. You can see it sticking out here: Then I put the 'rocks' in the bottom and turned it on. The bulb was 25w at first and nearly burned up the thermometer!! So I bought a 15W bulb at the hardware store (2 for $3) and that kept the temperature about 125 degrees. At least a temp I could work with!! (I rechecked the thermometer and it was still on .5 degree off so it recovered well). I cut some vent holes around the cooler and that helped some but not enough. So I read on here a thread about using a light dimmer switch to control the temp. I went to Home Depot and found just the thing ($15). It's similiar to this one: After playing around with the 'bator for a couple of days I got the temperature steady between 99 and 100 degrees (99.5-100.5 recalibrated). The humidity stays at a constant 45% without the sponge. Here is my complete set-up with eggs: I have it in my hall closet (no ventilation) with the door shut so don't mind the mess!! I plan on adding the wet sponge during lock-down to up the humidity. These are the silkie eggs that took a week to get to me so I don't know how many will hatch but I'm just happy there's only a very tiny swing in temperature and I check it 4-5 times a day! Other than the dimmer switch, it was all very cheaply done. I have my fingers crossed for little peepers at the end of the month!!