San Francisco has a plethora of free resources, events, and other awesome things. Below is a list of articles talking bout free things. If you're in the East Bay, you may want to take a look at Oakland Wiki's article "Free".
There is also a great guide called Freesorces. It lists things like shelters, where to find free food, crisis hotlines, medical resources, employment and education resources, housing/tenant resources,...and the list goes on!