I’d spend a few hours on ochanomizu. Honestly some cool stuff but the days of deals on what you are looking for are mostly over. There is always the off chance you’ll see some cool obscure thing you didn’t know you needed, and the store layouts are pretty unique that keep you coming back. Ishibashi has stores off ochanomizu in major metro areas of Tokyo that I honestly enjoy more. Better selection usually and they have higher end things, just with a higher end price tag that reflects that they were imported against a weak currency.
As other guys said, make sure you bring your passport book with you to shop in Japan. It’ll get the tax taken off in most places, or you can hit a store on the same street and get the refund in cash.