A good quality 1 carat diamond ring costs between $6,500 to $7,500 in retail stores, while online prices range from $3,000 to $4,000. The highest quality 1-carat diamond can exceed $10,000. However, if you're looking to sell your 1 carat diamond ring, you should expect only up to 50% of store prices if selling back to a jeweler. This is due to the fact that a jeweler will only be incentivized to buy if it's below current wholesale and manufacturing costs.