After my classes at the Prince's School of traditional arts, I found out about a few art stores that I don't think I can live without anymore. One of them is Cornelissen. It's an old little art supplies store with squeaky wooden floors located just by the British Museum. They basically have everything an artist might ever need from gold to pigments and beyond. Orders can be made online or on the phone. I reserved my order and went to pay in person because students get 10% off, which is a bargain if you are getting a bunch of stuff. I warn you though, going there will surly tempt you to get more art supplies. It's worth going regardless.