Receipt is a proof a purchase. In any case there is a dispute between you and the seller, the receipt will be the proof. I always keep my receipts after purchasing because I could track if any inconsistency exists.
--------------------------------------------------------------------------- ~ Change takes time, not at that time ~
It's preposterous that you would need one. Even if you were on per diem and had to tally your expenses, it's so little that you wouldn't bother.
--------------------------------------------------------------------------- In the end they will lay their freedom at our feet and say to us, 'Make us your slaves, but feed us.'