2 Chainz: You Found My Ring? Here's a Couple Benjamins!

2 Chainz is a ring fan ... so much so he rewarded a fan with cash when she found the missing bling.

The rapper performed Thursday night at Club La Vela in Panama City Beach, Florida and showed fan appreciation by spraying the crowd with water. Check out the vid ... it appears 2 Chainz's ring flies off his finger.

You can see staff and fans search for the jewelry ... when a girl pops up with the ring, flags down the rapper and returns it. For her honesty, we're told 2 Chainz handed over $200.