Covered garage from $11/day — shared shuttle with Marriott, every 15 min
Hyatt Regency SFO offers non-guest covered garage parking from ~$11.49/day via CheapAirportParking, OnAirParking, ParkON, and Way.com.
Shuttle is shared with the nearby Marriott Waterfront — runs every 15 minutes (4 AM - 1 AM) and every 30 minutes overnight (1-4 AM). One of the better hotel parking deals with covered parking and frequent shuttle service.

IHG hotel parking on Old Bayshore Hwy — shuttle to SFO
$10/day, free shared shuttle every 30 min — no hotel stay required
Shared shuttle with Hyatt, every 15 min — cheaper via SpotHero/Groupon
Fenced & gated lot, $24/day — but shuttle costs $5/person each way