Cheap with free parking, but insist on a room at the back!
San Francisco is ridiculously expensive, especially if you want to be within walking distance of Fisherman's Warfe. This place is fairly cheap for San Francisco, and is within walking distance if Fisherman's Warfe (if you don't mind a few hills) and the trendy Marina district bars. Parking is free, too, unlike other hotels which charge up to $50 a day for parking! 
However, unless you sleep like you're in a coma, you probably don't want to stay here unless you get a room in the back, facing away from Lombard Street. The window's aren't double glazed, and it's a constantly busy street, so it'll keep you awake all night. Walking down Lombard, it seemed that most motels were also single glazed, so I'd say the same applies for more or less all of them. We complained after our first sleepness night and were given a room at the rear straight away, meaning that this quiet room must have been available when we checked in. I wish they'd given it to us from the off...
All that said, if you do get a room at the rear, or if you're a heavy sleeper, you'll get a decent sized, clean room with free parking for half the price of most places around the Warfe. The corridors are tired and worn, but you don't sleep in them, so who cares?!