I can help you! We were just there 2 weeks ago. It's not Tequila Beach...it's Tequila Beach CLUB. Its right as you enter the fishing village of Majuhaul...about a 5 minute taxi ride from the port. You buy your ticket ($3pp) at the port and a taxi will take you there. The cost to get back is $2. We bought our Tequila Beach Club passes at the port. There was a guy selling them in a "hut" type booth in the port area. We paid $25 pp and had open bar, beach loungers, and could order Mexican snacks AND lunch...all you can eat. We ate and drank so much that we found it to be well worth our money.
A guy from Indianapolis, Otto, manages the place and will greet you as you come in and he'll show you around. A local, Ivan, was our waiter for the day and we tipped him well for his service. You can order from him or go up to the bar and order.
There are several places up and down the beach where you can buy food and drinks very cheap and they will let you use their beach chairs and will wait on you. The beach strip is narrow, but is pretty. I will warn you, the water in front of the Tequila Beach club was full of seaweed, but you can walk up the beach just a bit and the water is PERFECT. I have been on 3 cruises and Costa Maya has been my favorite port of all. I think it's because it was authentic and underdeveloped, and the locals were so friendly.