The hotel is gouging you with that pricing. Cozumel doesn't work like other foreign countries at the airport because of the taxi mafia. Don't bother pre-booking a ride. The pre-booked rides require prepayment, and if your flight is delayed or cancelled, you probably can't make changes to the reservation and it's nonrefundable. It's set up so that when you leave customs, go to the shuttle booth and buy your tickets in Pesos, USD, or credit card. Pesos is best, as you'll know what you're paying for and not have to do the calculations for the poor exchange rate in USD. Since there's no market competition, you'll see there's a long row of shuttle buses and they're filling them up and leave once the bus is full of people or there's no more room for luggage. You might wait 15 minutes or so, or you could be whisked away pretty quickly.
It's easier to have your Pesos purchased in the U.S. rather than the extra hassle after a long day of travel to find an ATM in Mexico. Your driver likely will not speak any English. You can buy foreign currency through Wells Fargo or if you have the Charles Schwab debit card, you can use that and not be charged transaction fees, ATM fees, and whatever other fee they want to charge. If your trip is early June, you'll want to order from Wells Fargo ASAP.
And with the taxi mafia, hotels and dive shops are prohibited from providing transportation, so have the hotel arrange your taxi for return to the airport and get a firm price before you get in the taxi. The same applies if you're using taxis generally in Mexico...get a firm price before entering the taxi and carrying exact change and use Pesos. The driver will usually give you the price in USD because he/she makes more money off you in USD.
Enjoy your trip!