Whats a great vacation spot for group of girls in their 20's. great night life/ beach, yet not too expensive?

Puerto Vallarta you will love it, you will find booths everywhere around town from guides offering boat rides for about 28 bucks free drinks! and lunch, make various stops at different beaches and waterfalls, I had a lot of fun there, plus the night life is great! they have a boardwalk all across the beach and night clubs across the street, many college students during spring break and you can get a hotel for as little as 25 a night