[Crani]

I suggest you get, if you don't already have, some gashappons, because they are cheap and just to spend does left-over dollars people may buy then and collections are always good to make money.
Jewelery (Necklaces, rings, etc...), key chains and straps are usually a good idea. Model Kits because Gundam and Mecha fans are everywhere. Cosplay articles may sell, since many people do cosplay and have a big interest in this type of things. Japanese candy are also a good idea, because people will buy it, just to try. And manga in japanese can have its benefits, since it is cheaper then translanted it may attract people.
Good luck with your business.