Cheapest/best kit available?
Another option is to get a kit from Zen Toolworks. They seem to be the best option for DIY kits in the size and price range I want (small and affordable).
Cost would be:
Kit - $329
Spindle - $70 - not the best but I think a good start and the benefit is it's built to fit. Could replace motor afterwards maybe?
Still needs power supply and controller board.
Zen sells a controller board for $130 but I think I could DIY one for a lot cheaper. The part used by the Mantis is unfortunately SMD-only. Other options?
Looks like total cost then of ~$500. Not great, but better than $350 + endless time.