The cost can include £50 notes, one gathers (8)
I believe the answer is:
collects
'one gathers' is the definition.
(I've seen this before)
'the cost can include ps50 notes' is the wordplay.
I cannot quite understand how this works, but
'notes' could be 'ec' and 'ec' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for collects that I've seen before include "Gets or gathers together" , "prayers" , "Assembles" , "Accumulates, collates" .)