The City of San Francisco through the SFMTA started a pandemic program where residents who are 65+ or have a disability can get an Essential Trip Card for taxi rides. The fee is $6 for a $30 credit, or $12 for a $60 credit per month. The program uses taxis to take people on essential trips like going to the grocery store, pharmacy or another necessary medical trip.
Call 311 (Mon-Fri, 9am-4pm) and tell them you would like to sign up for the Essential Trip Card. They will take your application over the phone, and you will get your card about a week later.
In addition, the Community Living Campaign might be able to cover the $12 cost. Call Cathy at 415-638-9183 for details.