Hat priced badly, going for a song (4,5)
I believe the answer is:
dirt cheap
'going for a song' is the definition.
(I've seen this before)
'hat priced badly' is the wordplay.
'badly' indicates anagramming the letters.
'hat'+'priced'='hatpriced'
'hatpriced' with letters rearranged gives 'DIRT-CHEAP'.
(Other definitions for dirt cheap that I've seen before include "rock-bottom prices" , "next to nothing" , "doing little damage?" , "Inexpensive (as muck?)" , "attractive to potential buyer?" .)