Question for people who live in Japan

Where the hell do I get a gameshark here in Tokyo?? I spend a lot of time in Shibuya and Shinjuku and I don't know where to get a friggin' Gameshark!!! I just want to be lazy and get all the items without working for it anymore. There's just too many charachters and items for me to do it all. My daughter takes up a lot of my time which I don't regret. I really would like to find one. It seems like Japan doesn't really like to use them or something. If you could help me I'd appreciate it. THANKS!!!!!