I was walking home a couple of months ago and I saw what I thought was a typewriter sitting in a plastic bag in someone's trash. Here (in Nova Scotia) we have bulk trash pickup twice a year, and folks often put out decent stuff so that other folks will pick it up before the garbage trucks come around. I looked closer and saw that it was an accordion. I snatched it up -- I don't play accordion, but I figured I'd give it a shot.
I left it in the garage in the bag for a couple of days just to make sure nothing was living in it. It was clean, so I took it inside. The parts that worked sounded OK, but the top row of keys didn't work at all, and there was lots of rattling inside it. Plus, something was preventing the bellows from fully closing. This weekend, I opened it up and was able to do some significant repairs -- the thing that was blocking the bellows (and the reason the top row of keys didn't work) was one of the reed blocks that had come loose. There were also a couple of free floating reed plates, causing the rattle. I re-attached the reed block, and stuck the loose reed plates in a ziplock for the time being. Now, both rows of keys work. I need to get some wax and put the two loose reed plates back on. They're on the left hand, though, which I'm not really using.
I spent a couple of hours yesterday figuring out some Christmas carols. My wife was pretty impressed both that I materially improved the performance of the accordion and that I could figure out some tunes. :)
Total cost: $0, maybe 45 minutes of time. I will have to spend some money for accordion wax at some point, though, to re-attach the two reed plates. There's also a missing button, so I'll buy one of those.
Honestly, I was pretty nervous about opening it up. I googled accordion repair and it seems extremely expensive. I'm not super handy, and I have no experience at all in instrument repair (I can change guitar strings, but that's about it). Once I opened it up, though, it was very straightforward.