Do-it-yourselfer's purchase (3)
I believe the answer is:
kit
'do-it-yourselfer's purchase' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for kit that I've seen before include "Set of equipment, perhaps for first-aid" , "Marlowe" , "Old song 'Pack up your troubles in your old . . . bag'" , "Specialised clothing or set of parts for assembly" , "Supplies" .)