The October 2026 book covers September 21 through October 18 — 28 days of Member-Only Savings that span the transition from the September back-to-school and household reset period into the October commercial calendar that the October guide documents: the Halloween Treats Sale (October 22-31), the Holiday Savings Book arrival (approximately October 19), and the beginning of Costco's holiday commercial season. The October 2026 coupon book's commercial character is specific and

Most Costco members have received the monthly coupon book in their mailbox. Most have glanced at it, found a few things interesting, and then gone to the warehouse without it. A smaller, more commercially savvy group of members treats it as the planning document it was designed to be — and the financial difference between those two approaches compounds into hundreds of dollars per year. Costco officially calls it the Member-Only Savings booklet. Most members call it the coupo