San Francisco residents complain frequently about skyrocketing rents, and it’s no different for visitors. Expect accommodation to cost upwards of $200/night in a reasonable hotel or motel, and less out of high season, although keep in mind that rates can fluctuate wildly at any time based on demand. To get the best deal, be sure to reserve well in advance, especially for summer and early autumn visits.
The San Francisco Visitor Information Center can provide help with finding accommodation, while San Francisco Reservations regularly offers cut-price rates on lodging. For B&Bs, contact Bed and Breakfast San Francisco. If funds are particularly tight, look into one of the many excellent hostels, where lodging rates start around $29.
Finally, other than a group-only campground in the Presidio, there’s nowhere legal to camp in San Francisco itself, so if you’re determined to sleep under the stars either in a campground or wild, head to any number of parks in the East Bay, down the Peninsula or in Marin County.