Takke, eVe asked where to buy not what to buy.
I would strongly suggest YesAsia.com . I have always bought items from them, and they're been great for me. They have really nice prices! The shipping costs are very reasonable also. If you do buy from YesAsia, please use the link at AHS.
If you decide not to use YesAsia, another good option is CDJapan.co.jp I have never ordered from them, but from what I've heard they are very good also. CDJapan does have higher shipping prices, however.
Buying Ayu merchandise, like Ayupans, is a lot more difficult. The best bet would be eBay, but you can't always find the things you want and it's often expensive.
