Did the same to Liverpool a few weeks ago in PA 28, came in at £60. Mind you, we did get a mandatory lift in a transit van from the a/c across the apron to the Big Yellow C(about 150yards) so i guess we got good value for money.......
Cardiff is still very reasonable for that big airfield experience. Dropped in there last week in PA28 again and came in at about £23, which is comparable to some much smaller GA airfields.
Mind you we did get a bollocking because apparantly we had been spotted by the guys in the control tower walking from our a/c to the flying club holding rather than wearing our hi-viz jacket thingy. The twr must be getting on for 600mtrs away. Good job i remembered to at least carry the thing or we may not have been seen atall......!!!