I would have the repairman show me the gear that's broken, then I would either order a replacement through Sears or an eBay seller and replace it. There are a couple of gears that are a PAIN to get to, but it can be done. Others are pretty easy.
The repairman is used to people who want quick, cheap fixes and have little attachment to their machines. His idea of what is "prohibitive" might be a lot lower than the cost that would seem prohibitive to you.
Give it a shot.