Economy supply, 50 florins (2-6)
I believe the answer is:
no-frills
'economy' is the definition.
(cheap airline ticket)
'supply 50 florins' is the wordplay.
'supply' is an anagram indicator (in a supple way).
'50' becomes 'l' (Roman numeral).
'l'+'florins'='lflorins'
'lflorins' with letters rearranged gives 'NO-FRILLS'.
(Other definitions for no-frills that I've seen before include "simple ..." , "Straightforward" , "Essential" , "Ordinary" , "Devoid of inessential features" .)