Is $450 enough for four days in San Francisco excluding accommodation?

Of course, you can spend $450 in one night, most anyplace. But you can have a fine time on that amount, and I'm gathering you are solo, too. The bus and Muni Metro, what you mean by subway, is $2, and you get a transfer good for 1 1/2 hours or something. Meaning that if you do what you went to do in under that time, the return trip is free. The only tour I would recommend is to go to Alcatraz, and I forget what that costs, offhand. In four days you can find plenty to occupy yourself by walking and taking the occassional bus. Maybe a taxi if you're nightclubbing and it's late. Central SF isn't really that big, if you don't mind walking. If I only had four days here, I wouldn't spend near that on transportation and tours......Even the ferry to Sausalito is around $10, last I heard....