Think to charge a pound (4)
I believe the answer is:
feel
'think' is the definition.
(I know that feel is a more specific form of conclude)
'charge a pound' is the wordplay.
'charge' becomes 'fee' (fee is a kind of charge).
'a pound' becomes 'L' (abbreviation e.g. Lsd - pounds, shillings, pence).
'fee'+'l'='FEEL'
'to' is the link.
(Other definitions for feel that I've seen before include "Perceive by touch" , "Perceive, sense" , "Find by groping" , "16A [JUDGE]" , "Be aware of - texture" .)