San Fran: Less Expensive Parking Near Moscone?

I'm planning a trip to San Francisco. I'm staying at a hotel five or
six blocks northwest of Moscone Center. The hotel wants $53.28 to
self-park a car and $59.28 for valet parking. I am sure there isn't
inexpensive parking around there but is there a way to park for
somehwat less (that is worth the trouble)? I looked briefly at
Moscone Center parking. One of the structures seems like it would
cost about $38.00 per day but I don't knmow if it allows overnight
parking and that is somewhat inconvenient to get luggage from there to
my hotel. So I need somehting closer. Any suggestions? Thanks.