Finally without appeal, he had paid a percentage (6)
I believe the answer is:
tithed
'paid a percentage' is the definition.
The definition suggests a past participle verb which matches the answer.
'finally without appeal he had' is the wordplay.
'finally' suggests the final letters.
'appeal' becomes 'it' ('it' can mean something attractive or appealing).
'he had' becomes 'he'd'.
The last letter of 'without' is 't'.
't'+'it'+'hed'='TITHED'
Can you help me to learn more?
(Another definition for tithed that I've seen is " Offered tenth of income".)