Roots: no appointment needed, Thursdays and Fridays 1-4 (9925 International Blvd, Oakland)
Wellspring Pharmacy (walk-ins without appointment, come at least half an hour before closing)
Many more options on the main page, including pharmacies (such as Pharmaca, Walmart, Walgreens, Safeway, Rite Aid and CVS), Sutter, Stanford, Kaiser and other providers, as well as other county sites (Contra Costa or Santa Clara)