You can use any sort of insulated container that is big enough for what you want to incubate. You need a source of heat and an accurate thermometer and thermostat. The hysteresis need to be about 0.5 degrees which means you need a fairly accurate thermostat. If you use an old fridge or similar you may need a fan to even out the heat a bit. One for males and one for females is good as well. I have two, each with 0.5 deg hysteresis and an electronic thermometer accurate to 0.1 deg C. One has a fan but I don't use it.