Report of one purchasing shelter for cattle (4)
I believe the answer is:
byre
'shelter for cattle' is the definition.
(byre is a shelter for cattle)
'report of one purchasing' is the wordplay.
'report of' indicates a 'sounds like' (homophone) clue.
'one purchasing' becomes 'buyer' (someone who purchases things).
'buyer' is a homophone of 'BYRE'.
(Other definitions for byre that I've seen before include "Stockholder" , "Shelter for cows" , "Cowhouse" , "Neat container" , "lower in here" .)