Another type of promise ring that is actually becoming quite popular is a promise ring that you give your partner. By giving them a purity promise ring you are promising to each other that you will save yourselves for marriage. It represents your stand to wait belief and wanting to keep yourselves pure for marriage.
They even have purity rings for those who didn't wait for marriage, but have now vowed to discontinue past lifestyles and remain abstinent. The rings are typically priced very reasonably, usually in the $20 range or a bit more depending on where you purchase it.