mexico resorts?

I want to go to mexico for my 25th birthday, probably 2 adults but possibly just me. I want a place with a swim up bar, a beach, spa and great food. I would like a place that has a lot of options or somewhere nearby to do excursions. I want to stay around $700/night or less sometime in the first week of january. Any places on the cheaper side but still nice?

Any insight is appreciated!