Food co-ops are supermarkets owned and ran by members, usually with a focus on providing natural, organic food and produce from local sources whenever possible.
Central Co-op[]
1600 E Madison St and Pine St, on Capitol Hill. On the web at centralcoop.coop.
Certified-organic market, with a large selection of organic produce, meat, fish, and poultry, grocery items, natural health product and a kitchen deli and espresso bar. Owner investment is $60, although non-members can shop at any time. Owners get additional discounts, such as 5% off on Member Appreciation Day--second Wednesdays--and monthly discounts for an extra 10%-off one purchase per month.
Puget Consumers Co-op (PCC)[]
Locations on Fremont, Greenlake, Kirkland, Issaquah, Seward Park, View Ridge, and West Seattle. On the web at http://www.pccnaturalmarkets.com.
The "largest natural food cooperative in the United States", PCC locations are quite large and offer pretty much the whole array of natural food products and produce. Membership fee is $60, non-members can shop too, with members getting additional discounts and member days twice a month on the 15th and 16th.