STM32 kits are again available.
Price remains $30 for the kit. Assembly/testing available for an additional $40.
MiniPCBv2 kits are $45, $70 assembled/tested. Both Teensy 3.2 and 400 processor modules are available. The 3.2 runs at 94MHz the 400 at 400MHz. Howard Dutton advises that the new OnStep Beta should be used with the 400, while ver. 3.16 remains fine for the 3.2.
I have limited supplies for S109 and LV8729 drivers available for $6 a unit when ordered with a controller.
For the adventurous I have some MiniESP boards and components coming. These require using surface mount components and flow soldering. These will be priced at $35. MiniESP