Thank everyone for the info/suggestions/comments.
Initially in this post, I just share some information, providing aliexpress.com(same boss as taobo) links, because I know many people buy electric parts there even with free shipment. Then I heard some bad news that they didn't ship or wrong parts, plus Nuno_pt suggest me to help, that's when I came in.
I've just asked our company's postal office that there is only one postal company to mail to USA, which is EMS China, although the price is high(240 RMB for 500g), I can cope with that. I've never heard ePacket, may be I've never mail anything abroad, may be that service is not available to my area, may be I didn't ask other places.
I'm buying 2DW232 from taobao now, the data code is 15-4, for which I've bought and tested before.
If everything is Ok(my spot check, postal, tests by recipients), and anyone need large quantity, a real group buy can be start later. But if that is still by me/taobao, I will again buy small samples first.
Again, this is a trial at my expense, I don't have any connections with the seller at taobao or the 17th radio factory. If anyone need some piece of 2DW232 for test, leave your comments here, my intention is to get more people involved in testing. For those who have said needing more than 30 pcs, lets see if there are something left.