Fee covering part of play rehearsal (8)
I believe the answer is:
practice
'rehearsal' is the definition.
(I've seen this before)
'fee covering part of play' is the wordplay.
'fee' becomes 'price' (I've seen this before).
'covering' indicates putting letters inside.
'part of play' becomes 'act' (a play is made up of acts).
'price' enclosing 'act' is 'PRACTICE'.
(Other definitions for practice that I've seen before include "Learn by repetition" , "'....... what you preach'" , "Exercise; professional business" , "Routine" , "The exercise of a profession" .)