Thank you for your advice.
The following is the bag I'd like to buy...
http://www.ebay.com/itm/SEE-CHLOE-c...297&pid=100015&prg=1006&rk=6&sd=261132744680&
Find the size not the same with the ones stated in regular stores. There is also pink colour which I've never seen... and just half the regular price. It sells also non-branded Longchamp-like purses from China, too. But the comments are mostly good for this seller, and it said there is tags, authentication card and dust bag... so just wondering if it's worth a trial.