These are probably the most original rings I’ve seen:
These are from a shop at Etsy called Souzou Creations which is based in Japan. And now that you know it’s from Japan, you don’t have to wonder. They make a lot of awesome and cute stuff over there that may probably look useless, but they’re really sellable everywhere.
These rings go about $10 to $20, depending on the design. There’s more: