Mr. S Beach is one that I recommend for couples who want less kids (not kid free) but don't want to pay the price of Nachi's $49.00 all inclusive.
All the beach resorts will be around $18.00 for 5 folks one way. Be sure to set the price before get in the taxi. Cozumel is not bad about hiking the taxi rates...but it does happen. And don't worry about getting back to the ship...there are more taxis than sand.
For families, I recommend Paradise Beach because the $10 wristband is a better deal for kids. The wristband is optional. Our 2 boys get it, but hubby and I do not. (we are shade people)
This includes unlimited 2 water trampolines and a bridge between then, an iceberg, kayaking, snorkeling, individual floats, multi people floats and land toys like a bungie trampoline...you can even climb a coconut tree.
Like Mr. S......Paradise Beach has no entrance fee. Their lounge chairs, tables, umbrellas, CLEAN restrooms, changing rooms are all free. All they ask is that you eat/drink while you are there ... which is fair. Paradise Beach even has free Internet at the bar.
All the food and drink are safe.
Both have independent vendors that offer motorzied water toys for an additional charge. Banana boats, jet skis, parasailing as well as massages on the beach.
You will have a great time!!