This is my home maid incubator...
this image is side ways white part is the top
so i built the over lapping corner to try and keep more heat and humidity in when i need to open it up i just lift it and try not to remove fully.
so for the costs..
1. plexy glass from osh $1 dollar they always have scraps from cut offs i did a double pain plexy glass to hold heat. if you only do 1 put it on the inside so that moisture does not build on wood cut out shelf..
2. i went to my local electronic store found a fan for $8 dollars it had a xtra part that i removed and i all ready had an 12 volt charging adapter for the fan..
3. light base home depot i used 2 just in case one burns out i have a back up 2- 75 watt bulbs and the base $1 dollar each and a cord $1 dollar as well..
4. hot water heater $8 dollars home depot..it works fine for me i get 40%-50% percent hatch rate for mailed eggs and 60%-70% rate for local pick up..
5. egg turner $40 plus shipping total of $52 dollars..
6. i have 2 digital temp and humidity in bator 1 is from incubator warehouse other from harbor freight..
total $ 92 dollars call $100 with bulbs..
the bator is 18 inches squared, when they begin to hatch and humidity goes up, i simple slide the white over laping top away very little to keep humidity from getting to high and i over lapped the materials by 1.5 inches hope this helps..