I'm probably in that boat on several machines.
Cyclone is probably my worse. I paid $1200 (after coming down from $1600). The family had medical bills, and was laid off from NASA (so i know it helped). At first, I thought i was doing ok. But as i dug into, I realzied just how much damage the game had (bad repairs, hacks, broken ramps, etc..). Plus, at the time the rampswere un-obtainum.
I'm a picky SOB, so I went overboard on bringing her back to her former glory (Boards repaired by Clive, New LED display, New CPR Playfiled, New CPR Plastics, New Glass, New GI boards relays, all new switches, LED's throughout, various new parts on the playfiled, new Ramp, Cab repair, ++++). I'm certain that i am at least $2500 deep into the game.... Not including my labor.
I probably have the most expensive Cylone in Texas....Oh well... It plays like a dream...