This page is a new thought, more coming as I think of them.

Many of the SF attractions have free hours or days, so if you are visiting at the right time and

Japanese Tea Garden

Free Mondays, Wednesdays, Fridays 9-10 am.

Arboretum

Free before 9am daily

SFMoMa

Free if you are staying here

De Young Museum & California Palace of the Legion of Honor

First Tuesdays

Always Free

Observation Deck at the De Young Museum

The ___ Bar atop the Marriott Hotel (the Jukebox)