Originally posted by Mohican My concern is if I buy from them how much custom duty I need to pay??
What are the laws in your country of residence? Customs duty is assessed at the border, is the responsibility of the importer (you), and often is zero for a particular class of goods depending on the trade agreements between the originating and importer's country. Such is the case with most photographic cameras and lenses imported into the USA from our "most-favored" trade partners. Of course, YMMV
As noted above, it is best to avoid using UPS and certain other shippers when importing. UPS adds a brokerage fee to the shipping to insure timely delivery of the goods. They pay the duty and then charge it back to you later. This is in addition to the initial fee.
Steve