Here’s a really common email that I get when I post a fully serviced machine, and the response that I always give.

Hi, I am looking for a sewing machine for my sister but I can only afford about $30-$40. Do you have any machines that fit that price range that would be good for a beginner?

I sincerely doubt you’ll find a serviced machine for $30-40.  Anyone who services machines in the city is going to charge $70 and up and that’s not including the cost of the machine.  That’s why my ads say that I’m selling them for less than the price of a service.

I don’t currently have any vintage machines that are in working condition that are not serviced. I’m not comfortable selling something like that because it may not work, or may have issues that will frustrate a beginning sewist especially.

You are doing the right thing though by looking at Vintage.  They’ll typically work better than new, and will be much easier to use.

Also, you need to find out what sort of sewing your sister will be doing.  If it’s basic clothing construction, or quilting, chances are a straight stitch machine is fine.  Zig Zag is a nice add, because it can help finish seams, but not 100% necessary.   If she’s wanting to embellish, she’d have to look at something more complex.