Proof of purchase (5,4)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">proof of purchase</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for receipt that I've seen before include "Delivery" , "Confirmation of purchase" , "Getting" , "Record of payment" , "Evidence of sale" .)