San Francisco

There are a lot of nice places to stay in San Francisco, I loved staying at the Pan Pacific! Check online for weekly rates, some will give you a deal.

http://www.expedia.com/San-Francisco-Hotels.d178305.Travel-Guide-Hotels

Or you could rent an apartment for the 2 weeks and buy your own food -
restaurants can be expensive in SF.
Here is an example
http://www.homeaway.com/vacation-rental/p253489

As major cities go, San Francisco is fairly expensive. As Calam has already said, eating out can be a very major expense. But if you're not looking for luxury in your sleeping quarters, there are any number of small hotels with quite reasonable weekly rates; many of them include a small refigerator and microwave as part of the room equipment. Coffee maker with daily supply of coffee is de rigeur virtually everywhere. My own feeling has always been that I'm not actually going to be living at my hotel. During the day I'll be out sightseeing. At night all I'm looking for is a comfortable bed. So whether or not there are nice pictures on the walls and whether the wallpaper matches the rug are not matters of major concern for me.

I second everything Lustig A said. I'll just add that, although SF is a really expensive city to live in, I didn't find it a particularly expensive city to visit. Reasonable accommodations are available throughout the city -- the last time I was there I found a place on the edge of the Tenderloin that was across the street from an X-rated theater. Some may consider that a minus. I viewed it as an amenity. The room was perfectly fine, and I didn't spend much time in it during the day anyway.

The price of food and attractions is in line with most major cities in the US -- I didn't find it much different from Chicago. Public transit is plentiful and readily available (the cable cars, though, are a special case), and the trams on Market-Embarcadero are a fun bit of history. There's a lot to see and do there -- just remember to bring warm clothes, regardless of the season.

I'm not necessarily suggesting you do this, but I'll just say it: if you're going to use the MUNI bus system to get around, you can often--but not always!--get away with buying a single fare with cash and keeping the receipt. The receipt is good for transfers and additional rides for 90 minutes from the time you buy it, but bus drivers usually don't check these things. Even if it's past 90 minutes, you can usually get on a bus and wave the receipt at the driver. I'd be surprised if he or she even gives you a second glance.

I'm with Joe. I took my whole family, rented a three bedroom home on Divisidero for $150/night, took public transit everywhere and thought it was very affordable. There are lots of tourist type activities that cost almost nothing.

San Francisco is very beautiful place. I had also visited there..

I have stayed at 3 different private homes/apt in San Francisco (and will be staying at another in a few weeks) via the 'Air BnB' website. It's like staying with friends. Sometimes places are available all to yourself. I have also stayed in Seattle, San Miguel de Allende and Guanajuato, Mexico through the service.s Of course common sense dictates that you select carefully and read the reviews posted for each offering.