Costco Wholesale

Built World

As of September 2026: Raised Kirkland Signature synthetic from ~$30 to $57.99 per 10-quart case, imposed a 2-unit weekly purchase limit, and capped Mobil 1 six-quart packs at 5 units per member.

Costco members now pay $57.99 for a 10-quart box of Kirkland Signature full-synthetic motor oil, up from about $30 last year. The chain limits purchases to two boxes per membership every seven days — its first motor oil rationing ever.

Updated Sep 15