Last summer I picked up a badly used International Milestone IV for $40. I think I got ripped off. The neck was heavily bowed, but I figured that a truss rod adjustment would solve that. Bought it, took it home, and discovered that it didn't put out any signal. Turns out, one of the pots had loosened, spun, and ripped the wires loose. Easily solved with a decent soldering iron to reattach the wires, and a wrench to tighten the nut.
Then I went to adjust the truss rod, only to find that it was already bottomed out with the strings nearly a 1/4" above the neck at the octave with them held down against both ends of the fretboard. After talking with Peavey service and a local authorized repairman, and deciding that the cost of having the work done would be far more than the value of the instrument, I decided to stick a washer under the capstan (it doesn't have the usual style nut) to put it further back onto the threads. To do so, I had to remove the neck, rout out the body to make room for the extended capstan, and trim the pickguard to fit. Removing the neck turned into its own 3-ring circus, as 3 of the 4 screws had the Philips head slots stripped, one so badly that I had to cut a fresh slot in it to turn it. Once the neck was loose, I discovered that the previous bass-butcher had tried to fix the string height issue by carving the neck seat to a slightly different angle using a chisel, leaving a rough surface that was anything but level. That took additional cutting and sanding to get it flat, and I added a shim to bring it back to a more correct angle and height.
Finally, I was able to put a washer under the capstan, reassemble the neck, and put the strings back on. The shim helped, but the neck was still heavily bowed. It took 3 thick washers to get it more-or-less straight, after which it became apparent that the neck had a slight "S" shape, so the strings couldn't be lowered below about 3/16" at the nut without buzzing while playing higher up past the octave.
I also noticed that the pickups sat really low, almost flush with the pickguard, and turning the screws (two of the heads were stripped out) didn't raise them. Upon removing the pickguard, it became apparent that whoever butchered the instrument had removed the pickups at some point and reassembled them without putting the springs back over the screws. The springs were stuck to the bottoms of the pickups.
At this point, the instrument is reasonably "playable" but will never be good. This is hands-down the worse instrument I have ever owned, and $40 was far too much to pay for it.