Ring for payment (4)
I believe the answer is:
toll
'ring' is the definition.
(a bell tolls)
'for payment' is the wordplay.
'for' becomes 'to' (eg both can mean 'in the opinion of').
'payment' becomes 'll' (I can't explain this - if you can you should believe this answer much more).
'to'+'ll'='TOLL'
Can you help me to learn more?
(Other definitions for toll that I've seen before include "Loss, damage; ring (bell)" , "Bridge or road tax" , "Crossing fee" , "Tax - strike - ring" , "Bridge or road charge" .)