It's been nearly 10 years but as best I can recall...
Found a nice G&L 2500 Tribute on eBay for a fair price. Hit the pay it now option. Offer accepted. Emailed the seller with preference to pay via money order vs PayPal. He said ok. Got sellers name and address, mailed the money orders and got the bass serial number. One week later reconnected with the seller via email, no response. Had his mailing address so I did a reverse phone number search. Before calling him, looked the address up on google earth, turned out to be a music store. I thought, how odd, why make the money order out to a person vs the store.
Looked the store up on line, viewed their used inventory and found what looked like the same bass for less money. Called the store from my office phone number and asked for the manager. Asked the manager if the seller worked there, he said yes. I asked if the G&L listed on eBay was still for sale, he said he didn't have any eBay listings but he did have a used G&L in stock (it was the same bass), so I bought it on a credit card and asked him to rush ship it to me.
After a couple of days I got hold of the original seller and asked him if he had shipped the bass, he gave some lame excuse as to why it hadn't been shipped yet. I told him I'd pay a premium to have it Rush shipped, he thought that was a good idea, so I told him I'd overnight another money order to cover the urgent shipping. Instead I called the bank and voided the previous money orders, which fortunately hadn't been cashed yet.
The next day I received the bass in the mail from the store manager, serial number matched the one the eBay seller sold to me. So I called the store up, talked to the manager and thanked him for the honest and prompt deal. Then I let him know that his employee had posted that same bass on eBay at a higher price. The manager looked into it.
Manager called me back later that day and apologized about his employee, who he had just fired. Turned out the employee (eBay seller) was taking photos of store inventory, inflating the price, selling the instrument on eBay and pocketing the difference. The manager offered to completely reimburse me and let me keep the G&L. Told him thanks, not necessary - terminating the employee was good enough for me.
Haven't bought anything else on eBay since then.