You can do some of the exams by just studying feedback, but not Principles of Flight and Performance. So many of the questions demand that you derive an answer from first principles, and it only takes a minor change to a question to make for an entirely different answer.
As for pricing, I am sure that the CAA had some "Time and Motion" gimp calculate that it cost sixty quid to scan an answer sheet and tap the results into a data bank....
Anyway, now that gubbins is out of the way, I am looking at doing the CPL round about Spring-time....