Here are some more sites for buying Chinese manga that I think very few people know about
:
They all ship from the U.S. The first 2 sites offer pretty cheap shipping via USPS Media Mail.
http://www.chinesecomicstore.com
Mostly used yaoi manga, but there's some shounen/shoujo as well. They also have a ebay store and I've ordered from them many times.
http://www.jcbooks.biz/
They sell new and used Chinese manga, and they just started an online rental service (the only online manga rental place I know of). They have a pretty big selection of 5000+ titles. I haven't tried them out yet but from my correspondance with them so far they seem pretty reliable.
http://www.comickingdomusa.com/
Prices seem somewhat cheaper than Yesasia but no free shipping. Haven't tried this place out yet.