Economical fee about to be deducted from £3.50 (7)
I believe the answer is:
thrifty
'economical' is the definition.
(similar in meaning)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for thrifty that I've seen before include "Frugal - economical" , "Not extravagant" , "Conserving" , "Careful and diligent in the use of resources" , "Sparing" .)