Anything under $300 is fair, if it works well. The repair is labor to get the oxide off and then see what it needs as far as sewing. Ifyou had to buy the machine, you are looking at $200 and up, possibly over $300. Does it have attachments? Sounds like may have been in a flood. There are new cases available, if the old one is too far gone. Parts are still available. You have done a great thing by saving the machine. After the repair, it will have value and you could always sell, but you probably won't want to.