Best bator and cheap don't go well together sadly enough.
In the small bator class the Hovabator1588 is the best for your dollar and generally the most reliable. It has a preset thermostat and a fan. All you really have to do is plug it in and let it go. Add eggs and water and wait. With a turner is runs about $168 from the manufacturer - GQF- plus shipping.
The cheap models like an LG can be picked up for about $40. You will regret buying one of those. The thermostat is control by you, the wafers can go out and be tricky. I wouldn't waste my time fooling with one. Been there. Done That. Never again.