Ask HN: Where can a developer stay super cheap or free in SF for a week?

Go southward and look for lodging in San Mateo or farther south. Make sure it's near a commute channel (bus or rail) the neighborhoods are nice and the fees are more down to earth.

I just saw this http://chezjj.com/

Airbnb is always a good option!

couchsurfing.org, great way to meet people as well.

hostels.com

Bingo!