I wouldn't do eBay unless she is willing to settle for one of the starter packages for sale. Most of those are poor sounding disposable instruments and can hardly stay in tune, (and factory second's too boot) but are perfect for a beginner who isn't sure they are going to stick with it. Even cheaper than renting. And sometimes you get a good factory instrument. My $250 Chinese outfit turned out to be halfway decent, but I also choose to buy from a local store so I could develop a relationship with somebody local.. Turned out to be a good choice -- I got a great teacher from their referral.

The used stuff on eBay is like a box of chocolates. But you can always look for local eBay items, where you can go and take a look at them before bidding, and a local vendor may have others for sale.

I'm running a "wanted" ad in the paper right now, mostly to hit the "hey, we have an old fiddle in the attic!" crowd. Got a call from a repair guy that has a good reputation, but no one had thought to tell me of him, so I'll go out and look at his selection. And I looked at an old lady's violin today, a 1927 German model, what looked to be a student model. It wasn't a great instrument, and it wasn't really in playable condition, but it had decent tone and with a new bridge and nice setup, it would be a better instrument than one of those Chinese or Korean starter kits. The bow was definately a student model -- poor cut of wood and maybe not worth re-arching, but still way better than one of the fiberglass bows they put in these kits. Wish I had run across one of those when I was buying my first fiddle... but then I wouldn't have had a clue what to look for... not that I really know that much now!