I can't remember the price - I think it was $25/pp. However, it should be listed on their shore excursion list at their website (disneycruise.com). The gentleman we had was very funny and showed us all the famous spots -- and told us some of the local gossip. We liked him so much that when it was over, I gave him a hug and an extra $20. He looked like he was about 90, but sure didn't act it.
The van was so comfortable that at one point I got caught dozing!
They stop at the fort and many other spots and you get so many minutes at each. The only thing, bring some $1 bills. Every stop has locals who are the tour guide for that stop and they "sort of" expect a tip at the end. We just gave each one $2.00. There were only three stops like that I think.
But for the price, you could not get such an extensive tour of the island by taxi! We even got to go to the "rich side" of the island and see the resorts and casinos. He also took us by the house that Prince Edward and Mrs. Simpson settled in after he left the throne and they were married. I found it well worth while. At the end, they leave you off at the straw market. After we shopped there, my DH and DD went to the Pirate museum and I went back to the ship.
BE PREPARED to be haggled to buy things. But really, you never feel threatened or anything -- just wave them off. And when you shop the straw market, do not buy the first item you see. If they won't haggle, go to another table. Someone else will have it and give you a better deal.
Have fun....