| Go to Argyle St. in Mong Kok. Pick any of the smallers stores... Avoid the big chains like Broadway, Fortress, Tai Lin, etc. They have like 10 stores each down that block now, and their prices are always the highest
But if you go to an independant store, you'll find what you want for a LOT cheaper than the chain stores.
Ask for "sui foh" products - these are the imported products from Japan (and elsewhere - I have a Casio watch that is from Finland lol). The differences (besides having a lower price) are that they will use a plug that is not to HK standard, and will be 110V (although most electronics use AC/DC adapters that are multi voltage, and all you will need is a plug adapter). Also, the warranty will be direct with the manufacturer, instead of with the local rep in HK. Sometimes there will be no warranty at all, so be sure to find out!
Local stuff is called "hong foh". If you are just window shopping, look for the Chinese symbol "water" - that's the "sui" in "sui foh"
Shop around! If they don't have a price listed - ask! They aren't trying to rip you off, they are just being competetive. If you ask enough places, you'll get an idea of what the lowest price will be.  | 
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