Blue Nile is a site you can return things to within 30 days if you don't like it. You can return or exchange. Their service and return policy is fantastic. That's a site if you're hesitant about online that is worth looking at. I would NOT go through Ebay OR
Amazon, as you have no idea what seller you're REALLY dealing with.
If it's to be a "placeholder" Id lean towards a band, bec then you can include it in your wedding and have it as a band you can wear in place of your main wedding ring or set, or add to the set.