Payment offered on a regular basis (3)
I believe the answer is:
fee
'payment' is the definition.
(thesaurus)
'offered on a regular basis' is the wordplay.
'on a regular basis' indicates alternate letters.
The alternating letters of 'offered' are 'FEE'.
(Other definitions for fee that I've seen before include "(Entry) charge" , "price" , "Sum payable to professional person for services" , "Money paid for professional services" , "Sum payable to, say, barrister" .)