I have only had sex once my whole life at the age of 21 with my best friend. I do not regret it at all!! I love him too much. However, I do feel like it is best for me to tell him that I do not want to be friends with benefits anymore. I want to share my body with someone I truly love (never been in love before)...you know...someone I can see myself with for the rest of my life!! :)
You can buy them online, I've seen some pretty ones on ebay. Also try some jewelery shops, I saw one in a gift shop once.
Also sometimes certain churces also sells purity rings, you could ask around.