My boyfriend and I booked a corridor room for two nights with sharing bathroom and shower. This place is located in Powel street, close to union square, in the heart of financial district, which Is the shopping paradise. It is perfect if you have few days to visit the town: 30 min beautiful walking to pier 39 and waterfront via chinatown and little Italy; 2 min walking to cable car and major transportations.
The room is clean and the receptionists helped with information and suggestions. Bathroom and shower are also really clean and usually shared with no mote than 4 rooms (it's a good option if you have restricted budget and SF is super-expensive).