"in SF" - that is not affordable. If you are trying to save money you live somewhere on the BART or Caltrain and take the train into the city every day. My rent in East Palo Alto the year I was there was $400/month all utilities and internet included, for example. Is commuting into big cities like SF and NYC every day by bus and train miserable? Yes. But thousands and thousands of people do it because it is affordable and they have families or retirement they care more about.