Sounds like a good deal if you can get it for that price and there aren't any parts that require replacement (definitely make sure you test it out first).
If you're pretty handy, or just curious like I am, then you can probably service it yourself. I found a service manual online and could point you to it if you wanted.
I'd never opened a sewing machine up before but with a bit of patience got mine cleaned, serviced and lubricated in about 2 hours. However, when I do it the next time it shouldn't take more than 10-15 minutes. The downside of doing this yourself is that you don't know what normal wear looks like vs worn parts...then again it's a gear driven machine so there aren't any belts to replace either.
...just something to keep in mine if you wanted to try and save yourself a couple bucks and if your DIY fix isn't tamed by just making gear