FREE Finish Quantum! This is a neat deal and kind of liberating from your old sub-par dishwasher detergent. From December 7th to December 9th, trade in any other empty dishwasher detergent box and purchase a new box of Finish Quantum 20ct and get a full refund! Via mail in rebate or specially marked boxes. This offer is valid at participating Wal-Marts, so click here to find a location near you.