Regular payment covered by parent, a lifesaver (6)
I believe the answer is:
'regular payment' is the definition.
'covered by parent a lifesaver' is the wordplay.
'covered by' says the answer is hidden in the clue.
'RENTAL' is hidden in the letters of 'parent a lifesaver'.
(Other definitions for rental that I've seen before include "Cost of hire" , "To do with a letting" , "Money paid for hire" , "What's offered by a letter" , "Hire charge" .)