There is a lovely little shop called "Didi's" in Kathmandu run by women, which supports village projects. You can visit the workshop and see all kinds of craft's being made and then purchase for reasonable prices.
I would steer clear of factory tours of carpets and other "attractions" as often they will be run by unethical people who exploit children (child slave labour). Walking throughout the streets of Kathmandu you will likely be approached by people offering a carpet tour, so please either research prior or ask a lot of questions to avoid supporting such organisations. over 7 years ago