Email the seller asking about the instrument, but you can also ask for a telephone number and address. If you're seriously considering buying the instrument, call the phone number; and verify the address with an on-line search.
Ask detailed questions. Like Jazzyvee said, fraudulent listings or usually made by people who know nothing about the instrument.
Ask for more pictures. Fraudulent listings are usually made with stolen pictures and text; the seller of fraudulent listing won't have more pictures.
Determine whether the instrument comes with a hard case. Ask how it will be boxed.
Another thing you can do is post about the listing in the Seen on Ebay section of our board, and let other members know that you are seriously looking at bidding on the instrument. The downside here is that you may draw potential bidders to the instrument; the particular instrument may be one that a certain club member has been patiently watching for during the last two years. On the other hand, many club members will defer to a fellow club member who's announced their intention to bid. In those situations, you need to let your fellow members know if you quit bidding on a listing so that they still have opportunity if they're still interested. The big thing here though is that your fellow club members may be a able to spot a fraudulent listing. Somebody may recognize the instrument. There may also be a club member who lives close to the seller and can actually see the instrument in person.
Following is text that I copied from one of my previous posts. It pertains to a particular ebay listing, but the general idea should be helpful.
1 - The listed seller had a feedback rating of 2. This in and of itself isn't bad, and fraudulent listers have hijacked other users' accounts with lots of feedback, but it should draw your attention. Often a fraudulent lister will set up a new account and stock it with a few low doller sales to make it look legitimate. In this case, clicking on the seller's feedback, the two previous transactions had nothing to do with music equipment. Here the user account may have been hijacked, or it may have been set up by the scammer.
2 - It was a short listing; it appears that it was a three day listing. Fraudulent listings typically run for a short period, hoping to scam someone out of their money before others discover and report the fraud and have the listing removed. Again, this in and of itself isn't a dead giveaway; there are from time to time legitimate listings that run for a short period. But it's a big hint.
3 - It's a relatively expensive item with a relatively low starting price and no reserve. Again, in and of itself, not particularly bad; some people list with low starting prices and no researve on items that they know will generate interest, but when they do, they usually have a long listing time. Coupled with the three day listing, this warrants caution.
4 - And this one is a big hint, the listing has a line near the end that says something to the effect of email me at my office email address for by-it-now price and gives a different address from the seller's user address. You should only use the user address and go through the Ebay system. Here the scammer is trying to get people to contact him outside the system. This hint, especially in light of the previously mentioned hints, seals the deal; it's a fraud.
5 - This particular listing includes a hint that it's a repeat of a previously fraudulent listing. The line at the end where the scammer wants you to contact him at a different address also includes something to the effect of or your bid will not be considered. This is also a big hint, but in this case consider was spelled concider and was spelled that way in a previous fraudulent listing. So not only were the pictures and description copied and pasted from previous listings, so too the misspelled text added in a previously fraudulent listing was also just copied and pasted again.
