We've only bought on ebay once and were very pleased with the transaction.
We were browsing through the autoharps looking for yet another Model 73 (black "A" style with 12 bars). We share these with kids in conjunction with our school programs and are always looking for a deal on another one even though we already own about a dozen of them. Suddenly, there it was - one of the first (if not THE first) model 73s ever made. From the pictures it was easily identifiable as vintage 1898. We e-mailed the seller with several questions and he seemed to be very forthright with his answers. We paid $76 plus $20 for shiping and when it arrived it was exactly as advertised - no better, no worse.
We're still doing some repairs on it but we're using it on the stage and are delighted with it.
On the other hand, your milage may vary.
Bev and Jerry