Taxi fares are fixed ,so do ask a price before you get in.The normal fee is about $11 pesos.There are also plenty of rent a car places along the hotel zone.You can also get a ferry-taxi along the coast to another beach along the hotel zone for a small fee.
If you take the bus from Cancun to Tulum, take a taxi to your hotel from the Tulum bus station in the center of town. It costs $3.00USD and is the quickest way to find your hotel.
Walking or asking for a ride from someone in your hotel saves you $3.00-5.00 each time. There is always bound to be someone who is going into town at the hotel you are staying at. Take taxis only when it is absolutely necessary like at night time or when you are going to visit a ruin site farther into the jungle.