Husband and I were given a gift of lodging for a vacation. Where are some of the cheapest places to go factoring in flights and food/drink expenses?

So we have free lodging pretty much anywhere. However, it's through RCI so most of the places would be highly tourist areas. We've heard mixed things about Costa Rica and Puerto Rico actually being cheap. Mexico? Also, cheap flights will be a must. We really can't afford $700+ per flight.

Ideally we want to go somewhere warm and relaxing, but would be open to any suggestions!

Also, sorry if posted in wrong area. I've looked for other thread and articles but all of them seem to focus on the cheapest lodging so it doesn't help much.