Mine isn't too bad compared to the others I've seen on here.
Rollergames for $580. At the time this was a lot for me to spend and I really wanted Rollergames. At least I talked down the $700 asking price. The playfield was worn down to the wood in several locations, 2 digits on the display were out, half the GI didn't work, broken plastics, and the Wall had some steel welded to it from it being broken. I drove north of Milwaukee from the western Chicago suburbs to get it as well. I decided to hand paint the playfield with paint markers, print out graphics that looked bad, and clear coat over top.
A few weeks later another Rollergames appeared for sale in Rockford that looked real nice. I asked the seller if it said Diamond Plate between the flippers, which it did. I ran out there and paid $700 for that one. After spending a ton of time repairing the playfield on the first one, I took the best parts from each to make the DP the best I could to keep while I put the older one up for sale. Luckily I got $600 for it, losing little in the way of money just a lot of time painting.
I guess this might not count as the worst amount paid just the one that required the most work. Had I waited a few weeks longer id have ended up with the better one I still have now and wouldn't have had to go through with the work involved in the other or the drive.