Inexpensive fashion seen on street (6)
I believe the answer is:
modest
'inexpensive' is the definition.
(I've seen this before)
'fashion seen on street' is the wordplay.
'fashion' becomes 'mode' (synonyms).
'seen on' is a charade indicator (letters next to each other).
'street' becomes 'st' (abbreviation).
'mode'+'st'='MODEST'
(Other definitions for modest that I've seen before include "self-effacing" , "Inexpensive" , "Unassuming or unprententious" , "Unassuming; small" , "Humble, unpretentious" .)