When the rock walls were first introduced there was a fee. I believe, if memory serves me correctly, that they no longer charge. Also, not positive about age limit (I am assuming you mean minimum age) but they do require that anyone under 18 must have a parent or guardian sign a waiver before they can use it. In a previous post I mentioned on days at sea that they had instructional sessions. When the ship is in port there are usually two open climbing sessions (9-11 am and again from 5-7 pm).