When you're on the public website (sftgg.org, but NOT logged in as a member), one of the top-level navigation tabs is Hire A Guide! Click on that, scroll down, and you'll see the rates.
I'm also copying them here:
These rates represent minimums recommended by the San Francisco Tour Guide Guild. Individual guides may adjust pricing based on language, experience, season, or the complexity of your program.
Tours & Narrated Programs
English-language tours
$350 minimum (up to 4 hours)
Then $75 per additional hour, rounded up to the next full hour.
Foreign-language tours
$375 minimum (up to 4 hours)
Then $85 per additional hour, rounded up to the next full hour.
Meet & Greet / Airport & Transportation
English-language services
$250 minimum (first 4 hours)
Then $50 per additional hour.
Parking/BART/transportation reimbursement required.
Foreign-language services
$275 minimum (first 4 hours)
Then $55 per additional hour.
Parking/BART/transportation reimbursement required.
Out-of-pocket expenses (parking, tolls, BART, rideshare, and other transportation) must be reimbursed. Additional allowances may apply for travel time to airports, printing signage or manifests, cell phone usage, and meal periods when appropriate.