Not really. I needed a new battery some years ago and bought one from an eBay seller with a high rating. It would not properly fit in the battery slot, requiring the cover to be forced closed. I didn't like that, and expected the latch to be damaged by this eventually.
One nice thing about eBay is, they stand behind every purchase as long as you follow all the rules and a few additional things.
1) When the package arrives, video the opening so you have proof of what was delivered. Be sure to include in a single, continuous recording, the tracking number on the package, opening and removing the item, and a close up of the label and item.
2) Make sure you meet all deadlines. Some vendors will delay shipping, knowing the package will then not arrive until after the 60 days from ordering. If it does not arrive in 45 days, file a refund request promptly.
3) If all else fails, you can dispute the charge on your credit card. Just keep all the details and provide them to the credit card company. They won't mind the volume. Again, observe the 60 day time limit.
I've never lost a dispute this way. I did order a second battery from another vendor and it worked fine.
Oh, one other thing, NEVER, NEVER, NEVER buy a USB flash on eBay. If you pay enough, you may get a valid drive, but there are too many cheats to make it worth while. Simply plugging it in to see if it works is not enough. You have to fill the drive with data and then verify the data, to detect the fakes that are actually much smaller than claimed. There are a few programs just for this.