I would recommend building one from an old fridge (i used a glass front coke fridge myself). Old fridges are cheap (or free) and all you will need is a thermostat, heat tape and small fan. Should cost under $200, with the thermostat being the most expensive part.

From what I have read maternal incubation works however there may not be a 100% hatch rate. I prefer to play it safe and incubate.