It really depends on the vendor.
There are eBay vendors who only have 5 or 10 transactions on their seller’s history. There is no way I would buy anything from a seller like that, much less something expensive like a wedding ring.
Then there are eBay vendors who have many tens of thousands of transactions on their seller’s history, with 98% positive reviews from customers going back 10 years, and a clearly stated return policy that would allow you to return the ring if you don’t like it. I have heard very good things about one eBay vendor called “Lord of Gem Rings.” I would consider purchasing from someone like that. I’ve never done it, however.
However, you don’t have to go through eBay to get a good deal.
If you want to go through an actual business or company online, I would highly recommend Amazon or Overstock.com. They have amazing return policies and they have a really nice selection of jewelry, wedding rings, engagement rings, wedding bands, etc. etc. If you don’t like it, just send it back (and DO insure the package for good measure in case it is somehow lost by UPS or whatever).
We actually got DH’s wedding band from Sam’s Club. It’s a simple, 14k gold band which was exactly what he wanted, and we got it for a fraction of the price that we would have paid if we had gone to a private jeweler or a chain jeweler such as Jared’s. I’m trying to remember but I think we paid less than $200 for his ring at Sam’s Club. Our local family jeweler quoted us something like $500 or $600 for basically the exact same ring. That was a no-brainer!
I think you are smart to avoid the jewelry stores and chains. Gold is gold. Why pay the mark-up? So that you (general “you”) can enjoy standing in a fancy jewelry store, looking at the sparkly chandeliers, sipping a “free” cappucino and listening to piped-in Mozart while handing your credit card to a man wearing a suit?
Just look at these prices…