After prohibition, 500 bear cost of music platform (9)
I believe the answer is:
bandstand
'cost of music platform' is the definition.
'bandstand' can be an answer for 'platform' (bandstand is a kind of platform). I am not sure about the 'cost of music' bit.
'after prohibition 500 bear' is the wordplay.
'after' says to put letters next to each other.
'prohibition' becomes 'ban' (ban is a kind of prohibition).
'500' becomes 'D' (Roman numeral for 500).
'bear' becomes 'stand' (synonyms).
'ban' next to 'd' is 'band'.
'band'+'stand'='BANDSTAND'
Can you help me to learn more?
(Other definitions for bandstand that I've seen before include "Park structure for musicians" , "place to play?" , "Outdoor music platform" , "Outdoor platform for musical performances etc" , "Outdoor concert platform" .)