You have to take a taxi to Playa Del Carmen. The taxi coast is $16 one-way. There are shuttles from Seaside Suites, but they take too long. Get dropped off anywhere on 5th Avenue. There is great shopping and restaurants. Be sure to spend the whole day there. Remember to bicker with store owners for cheaper prices - they love it.
Also, eat at local places and stay away from Senior Frogs and Carlos and Charlie’s. They are way overpriced and the food is not like the locals make it!