Every so often I’d buyer needing to be paid (3)
I believe the answer is:
due
'to be paid' is the definition.
(I've seen this in another clue)
'every so often i'd buyer' is the wordplay.
'every so often' means one should take alternating letters.
'id'+'buyer'='idbuyer'
The alternate letters of 'idbuyer' are 'DUE'.
'needing' is the link.
(Other definitions for due that I've seen before include "deserts" , "Expected at any moment" , "Deserved or unpaid" , "Escort" , "Ripe for payment or arrival" .)