Tokyo has an electronic market- Akihabara, where there are many stores. It is a must visit for any tourist. Many stores with multiple levels. And each level specializes in a particular electronic item. You name it and they have it. Watches, Iphones, cameras, speakers, music systems, lap tops, gadgets and more gadgets. One goes mad with the choices and brands available.
I bought some lenses for my camera and few things that my boys had asked me to. You can spend full day in Akihabara.