I know there are a few resorts that have all-inclusive deals. I would mention names, but the iron fist of this news group makes it so I only visit when the other site is down. There is a beach called Nachi Cocom that has a $32 beach break or a 20% coupon at cozumel insider. Paradise Beach has $5 wrist bands for water toys and no admission charge. I have opted for Melina resort which has a $40 all-inclusive with a limited number of guests a day.
Hopes this helps.