As discussed in this question, a US to Europe Plug Converter Travel Charger Adapter for Apple iBook/MacBook could be used. However, this particular entry in Amazon would cost ~14$ and I am located in San Francisco for September. I tried to ship it to Greece, but Amazon wouldn't accept that.

So the questions is if there is this particular hardware piece somewhere in San Francisco, so I can go and pick it. Please recommend!

Sorry, if this is not the most appropriate question, but I am really desperate on finding one!