These are my main sources. There are others I hit every so often, which I’ll add eventually.
Hobby Link Japan
This is a good place to preorder new items, but you have to be quick! Check OFTEN, and preorder as soon as you see something new. Once the items are in stock, there might not be enough to go around. Older stock doesn’t hang around too long. SAL shipping is a good bargain, and I’ve never had a problem with these guys.
Good prices, but the shipping will get you (they’re in Hong Kong). They often get new shipments of older limiteds, so check often. Pheno’s forum members get a discount!
Tisinc99.com (website) / tisinc (ebay auctions)
They have a pretty good selection, and usually ship same day. Fuzors and Genesis kits’ prices have been falling lately. Sometimes the ebay store has cheaper prices, but sometimes the website does. Check both! One warning: they get overloaded in December (I wonder why???), so there could be delays or mistakes.