Dispensary Trades Free Pot for Cans of Food California facility brings in 11,000 pounds of donations for food bank By Katherine Kuzma-Beck, Newser User Posted Dec 29, 2010 8:10 PM CST Promoted on Newser Dec 30, 2010 2:34 PM CST 21 comments Comments File photo of a joint-in-progress. (AP Photo/Jae C. Hong) (User Submitted) – Want to know the secret of getting a whole bunch of canned food donations? Offer free pot. That's just what a medical marijuana dispensary near San Francisco did over the holiday season, reports AP. The Granny Purps dispensary collected 11,000 pounds of donated food by offering complimentary marijuana cigarettes for every four cans of donated food. Patients were limited to three freebies a day. In the end, the dispensary gave away 2,000 joints and donated the cans to a food bank.