here's a helpful little list for ya:
Cannabis Patients' Cooperatives
CannaMed Care Center
1222 Sutter St
(415) 885-8007
Grass Roots Clinic
1077 Post St.
(415) 346-4338
I went to GRC today.. they only had Sour Diesel, Grapefruit Kush, and I think a purple strain for their clones.. this was kinda late in the day, so the best time is probably when they open. I got a Sour Diesel clone for $12.
Also, hit up Sanctuary. I went there today, and they had some nice-looking clones. My memory sucks, but I remember they had Mazar and Hindu Kush x Skunk #1. I got the latter clone for $15.
Sanctuary
669 O'Farrell
(415) 885-4420