Crossword Puzzle Redeemable proofs-of-purchase, once

Clue: Redeemable proofs-of-purchase, once

Box office purchases (abbr.) (TKTS with 4 letters)
Office purchase (REAM with 4 letters)
OfficeMax purchase (e.g. FELTTIPPEN with 10 letters)
Post Office purchase (e.g. BOXNUMBER with 9 letters)
Office manager's purchase (REAM with 4 letters)
Box office purchases, slangily (TIX with 3 letters)
Box-office purchase (TICKET with 6 letters)
Offering discounts for the purchase of a dozen delicious mice? (OWLPRICED with 9 letters)
Offloading of a purchase (RESALE with 6 letters)
Office Depot purchase (REAM with 4 letters)