I think I got a steal because it was dirty.
I paid $37.50 or something crazy like that for a Janome MC 3000. I sewed on it for a day, and the walking foot made the needle slip out and it sounded all clunky after I replaced the needle with a new one. I looked at the feed dogs, and Holy Felted Fuzz, Batman, they were a mess! Now that I have it clean, hopefully it will be whirring again. I kind of think it started sounding funny and they sent it to the thrift store, thinking it was broken.
I could have sworn I looked at them and they were fine. Must need new glasses, lol.