T/T = telegraphic transfer. Explained quite well here:
http://www.binocularschina.com/guide/payment.h tml
Import duties vary greatly for different types of items. For example, there's no import duty on digital cameras as long as they only take still images. Webcams attract 4.9% duty but other cameras with a video function might have a rate of duty as high as 14%. An MP3 player is only taxed at 2%, unless it includes a radio, when it's taxed at 10%. Most clothing is taxed at 12% but baseball caps are only taxed at 2.7%. CD players are taxed at 9.5%, even if they incorporate a battery operated radio, but at 12% if they include a radio which can be operated by mains power. Strangely, radios themselves don't attract any duty. Silver, gold or platinum jewellery is charged at 2.5% but the imitation stuff is charged at 4%. (Are you getting confused yet?).
As you can see, things can get rather complicated. Start here to find out more:
http://customs.hmrc.gov.uk/channelsPortalWebAp p/channelsPortalWebApp.portal?_nfpb=true&_page Label=pageImport_Home
Once the import duty has been calculated, HMRC then calculate VAT. This is, of course, 17.5% on most items. However VAT is charged not only on the cost of the items but on the carriages costs and on the duty as well. (Yes, that really is a tax on a tax!). After they've worked out how big your bill will be, HMRC then add insult to injury by adding on a charge for doing so!
Use that link to try to find out how it all works. I hope, however, that you don't end up like someone I know who also tried importing cheap goods from China and is now stuck with 9000 plastic ponchos that nobody wants to buy.