We had to pay for the coach from the port to the main area. This was $8 each for a return and this was charged to your onboard account. We only did the cable car at €15 return. The one thing I didn't like here was being constantly pestered by taxi drivers to take tours with them. They are everywhere. Didn't make for relaxing time onshore.
I liked Tenerife, we walked to the sites but there was a coach if you wanted it. Lots to see and do. We found a small museum for a castle, underground, just stumbled upon it really. Thought it was a subway but it was entrance to the remains of the castle. It was free of charge and quite informative. The 'opera house' is worth a walk to, spectacular bit of architecture.