1970 CB350 bought for $200.. missing carbs, rear brake lever, battery, clutch/brake levers, center stand, key switch, drive chain, rear taillight, air filters, throttle/tach cable, mirrors, horn, header had a missing flange, cracked speedometer..
And it had these dumb glass pack mufflers. I new it was never going to be a pretty bike, but I got it all tuned up and had a lot of fun blasting around town on it. About $250-300 worth of parts into it, then I got tired of riding around on the stock tires and installed some new ones before selling it.
1973 Yamaha MX360 given to me for free by a friend of my dad's who had ice raced it as a younger lad. Cleaned the carb, converted for pre-mix, rode it around my parking lot a couple of times and seized it due to a big exhaust leak and/or gunk in the bottom/top end.
Had a friend weld the crack in the pipe, flushed the bottom end, rebuilt the top end with a fresh piston + rings, hone job, small end bearing, new gaskets all around. Rear shocks stuck, no rebound in front fork.. useless tires, laid it down on the grass once and decided it wasn't for me. Sold it for $400 to an old dirt rider who liked the old thumpers.