The port at Ocho Rios in Jamaica is located in town. There were many local tour guides waiting to take you on tours of the island and local attractions at a much lower cost. Of course, you don't have the same assurances you get from the cruise company, but, it was really easy to secure a reputable tour. For ten dollars each we were taken to Dunns River Falls, dropped off, for two hours, and then picked up for the return trip. Dunns is only about 15 minutes from the port. We come back to the ship, ate in the Italian restaurant, and went back out to find free wifi and souveniers.
In Grand Cayman, we were tendered in to the port. At the entrance we could have selected a tour, but we decided to take a local bus (mini van) to the Turtle Farm. The vans marked MB1 or MB2 will take you to many attractions for only $2.50 each......each way. What a bargain.
In Cozumel, we took a taxi into town for $8 for two....."ocho por dos." We shopped, returned to the ship for lunch at the Blue Iguana, and went back out for free wifi (at Poncho's there at the port). Don't tell them I told you!