You could try looking up Japanese stores that sell cds in your area. But it would be hard. Even if you do find one, the prices will most likely be quite high.

Your best bet is the internet. I've been buying online for about 6 years now and haven't had a problem yet. It just depends on where and who you buy it from. I started my Utada Hikaru collection through ebay. Always use paypal! That's your best bet for security if buying through ebay. Make sure to check the seller's feedback to see if he's legit. You don't wanna get scammed. But even if you do, you're still protected through paypal and can get your money back.

Amazon is also good, reliable, and safe. But it's really pricey, even in the used section.