Just built a controller.
Bill of materials:
Inkbird All-Purpose Digital Temperature Controller Fahrenheit &Centigrade Thermostat w Sensor 2 Relays $16.50
4x4x4" junction Box $9.38
8' 16/3 power tool cord $9.56
15A Duplex Outlet$2.19
Total: $37.63
The Temp controller is more than I needed, it does cooling as well as heating, and since I had it, I wired up bot sides, with one plug in the dual outlet for the heat side, and one for the cool.
I found a wiring diagram here, on a beer home brewing site:
https://loudmouthbrewer.wordpress.com/2013/12/10/diy-stc-1000-2-stage-temperature-controller-wiring-diagram-with-indicator-lights/
I didn't care about indicator lights, so I modified his wiring, to exclude them.
Stupid forum posted my reply before I was done, so continued in the next post.