Found a Dixell Chinese clone for +/- 12,5 $ to 14 $.
NTC sensor 1 $, PTC 1.4 $
Let's face it..what is a controller..a pcb with some screws in it, some small relays and a microchip.
It works or it works not, there is not that much that can go wrong with it.
Prewired box for a 5 HP: 123 $
Those small thermometers LCD with a button battery you sometuimes see in counters 2.85 $
Eliwell like thermometer 4.35 $
What do you think of it?