Cash maybe obtained from low-grade arsonist? (6)
I believe the answer is:
singer
This clue is a double definition.
'cash maybe' is the first definition.
(Johnny Cash)
'low-grade arsonist?' is the second definition.
(someone who singes things)
'obtained from' is the link.
(Other definitions for singer that I've seen before include "Coventry car firm" , "Someone of note" , "Song performer" , "one to celebrate?" , "Eg, tenor" .)