Food purchaser finally gets what's frozen (4)
I believe the answer is:
rice
'food' is the definition.
(rice is a kind of food)
'purchaser finally gets what's frozen' is the wordplay.
'finally' indicates one should take the final letters.
'gets' is a charade indicator (letters next to each other).
'what's frozen' becomes 'ice' (I've seen this in other clues**).
The last letter of 'purchaser' is 'r'.
'r'+'ice'='RICE'
(Other definitions for rice that I've seen before include "Type of grain" , "It grows in paddy-fields" , "Lyricist Tim - dramatist Elmer" , "Grain from the paddy field" , "Grain for food" .)