Parking is expensive in San Francisco! I went on SpotHero and found a garage right by the venue and a short walk to the hotel. The Clancy wants $75 to park (even though they verbally said $35).
147 Minna Street has $30 parking. Just make the reservation on Spot Hero and pay. You use the QR code when you get there from your reservation.
There are other parking options on Spot Hero as well. I think booking ahead is going to save everybody money!