Valid from May 7 to June 17, 2018 and may not be combined with any other offer. This offer is only available to members who pay by Masterpass and make a merchandise purchase of $100 or more (in one transaction, before taxes, applicable fees and shipping, unless applicable fees and/or standard shipping is included in the quoted price.) MAXIMUM of one (1) $20 OFF is available per member during the promotional period. Offer not valid for Costco purchases made in warehouse, in Costco Business Centres, on costcobusinesscentre.ca, or on purchases of Costco Cash Cards, App Store & iTunes Gift Card, Gift cards, certificates and tickets, travel, tires, membership, or membership renewals. Only Canadian Costco members in good standing may take advantage of this offer.