It won't be cheaper necessarily, but you can get tax rebate for it. Back then the GST was 8%, now I think it's 10%. Ask the shop if they have duty-free. Sometimes if you ask for "tax rebate" they may not understand. You will need to have your passport with you when applying for tax rebate.

You can find electronics / cameras / gaming stuff in pretty much any of the big chain stores. There's Yamada Labi, Bic Camera, Yodobashi Camera, and some others that I can't remember. These three are my usual places when buying electronics or video games.