Answer: receipt

AnswerCrossword Clue
RECEIPTPayment proof
receiptamount received
receiptwritten acknowledgment of receiving
receiptthe act of receiving
receiptto mark as having been paid
RECEIPTThere's no returning without it
RECEIPTProof of ownership
RECEIPTA written acknowledgment.
RECEIPTIt often says "Thank You"
RECEIPTIt often comes with a "Thank You"
RECEIPTExpense report attachment
RECEIPTSlip on a new piece of clothing?
RECEIPTReturn requirement?
RECEIPTRegister printout
RECEIPTTicket stub, e.g.
RECEIPTExpense-account item
RECEIPTExchange need
RECEIPTCanceled check, e.g.
RECEIPTVoucher.
RECEIPTProduct of a cash register.
RECEIPTAct of taking.
RECEIPTIndication of payment
RECEIPTReturn requirement, usually
RECEIPTStub, at times
RECEIPTAcknowledgment of a sort
RECEIPTSales record
RECEIPTProof of purchase
RECEIPTExpense report requirement
RECEIPTExpense report need
RECEIPTRegister output
RECEIPTPink slip, maybe