I've also done some woodworking - I would be interested in a repstrap design from wood.
I doubt, however, that you can get the steppers+electronics for under 100 unless you find a cheap source (free from printer discards?) for the steppers.
I just bought a Arduino Mega Clone (a "Taurino") with a RAMPS 1.4 board with a heated bed, homing switches, LCD display with SD card slot, timing pulleys and belt, thermistors, for $200. I am sure you can go cheaper than this if you forgo the SD card slot and LCD, requiring your PC to drive the printer.
The 5 steppers (Mendel types need 2 steppers for the Z axis) were $70.
I am still trying to make up my mind about which hot end.
I think guys have tried using a hot glue gun as a hot end, but without satisfactory results.
Any pics so far of your build?