Don't even remotely consider buying anything significant from any of the shops in the vicinity of Fisherman's Wharf. They are legendary for ripping off tourists in every way imaginable. And some unimaginable.
Many years ago when the £/$ rate was far more favourable I decided to buy a "souvenier" Olympus Muji compact camera while in SF.
I fond lots of good looking prices in a local mag and toddled off to the shop of my choice.
"Yes Sir we do have that model in stock" OK I'll take one I said expecting the price to be as advertised (even plus local tax - can't remember).
The price was then quoted as about 30% more than I expected, "why's that" I asked - waits for the reply.
"Because of the very special long life battery it requires that does not come with the camera". So trying to charge me about $40 IIRC for a battery I could by in Wall Mart for $4.99.
To the shopkepers amazement I declined, should have said "I'll take the camera and buy my own battery" but after they tried it on I didn't feel like giving them any of my money.
Even the shop I bought my camera from insisited the batttery was extra but this time it was in the sub $10 range, so not knowing about local battery regualtions I paid up, and still got a bargain.
So beware.
Oh and SF is a great place, make sure you book a trip to Alcatraz before you go as it's incredibly popular. We did an evening so got to see the sunset from Alcatraz
HTH
David