The low, low price of (4)
I believe the answer is:
only
'the low low price of' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for only that I've seen before include "Solely, lone" , "And no one else" , ". . . . the Lonely (sung by Roy Orbison)" , "Merely; single" , "See 6" .)