I don't remember the exact price. We usually just have them pick us up from the airport and catch a cab back at the end of the trip. If I remember correctly, the cost was about the same and it made the time you leave a lot more flexible.
Click on the link at the bottom right of the page. It gives you prices depending on size of vehicle. USA Transfers is a great deal!
I would highly recommend USA transfer. It's only $55 for round trip in your own private car. The best thing is you DON'T have to meet with them the next morning to schedule when they will pick you up to take you back to the airport and then try to sell you excursions. They will send you an email giving you the times they will be there (be sure to print off ahead of time). We even emailed them back and had them pick us up a little later with no problems.
Oups,forgot that little detail. Time to book them for the first time.Will be easier than taking a coach stopping int 10 different hotels before TTR (well that's how the Brits like it) -1st stay- or negotiating the fare at the airport - 2nd stay-