I recommend the overseas tourists to buy some Japanese sweets or snacks in case that you drop in a drug store or a convenience store.
I suppose that most of the shops in Akihabara sell good-quality goods at low prices. But there are always exceptions.
In our walking, the guide put Kitune mask on somewhere her body. Kitune is sort of a character in the play. You can put on Kitune in this walking as well. I am sure that the maze-like lanes in Kagurazaka would suit Kitune masks.