Qoutlet.com - This is my favorite store. They have great deals and are always updating with new items almost every two weeks! Definitely my main source of cute goodies. Their shipping is kind of high, but it's fast!

KawaiiGifts.com - Kawaii Gifts mainly deals with San-X items. The prices are kind of high, but the shipping is cheap so it works out in the end.

Daisuki Store - Masako is one of my favorite sack sticker sellers. Although I don't buy anymore, she always has new stickers straight from Japan!

Aside from those online shops, there are some great Ebay sellers. My favorites are: kawaiicorner, mytarson, tobypig, funnycastle88, janetstore. Those are all I can think of at the moment n_n