Not that it's all about price. The “cheapest” ring in our list belongs to Kate Middleton, the Duchess of Cambridge. It’s only worth about $137,200, but Prince William wasn't scrimping - the ring belonged to his mother, Princess Diana, who wore the same piece after agreeing to marry his father several decades earlier. Money can’t buy you to royalty, but it can buy you to the top of this list, which was what Richard Burton must have been thinking when he gave his ring to Elizabeth Taylor. How much is it worth? Let’s just say it's worth about 50 2013 Bentleys. Check out our list of the Top 10 Most Expensive Celebrity Engagement Rings.