Thamel Area, Kathmandu
Thamel area is full of gift shops (besides hotels and restaurants). Most of them carry pretty much similar things. Jewelry shops with silver and semi-precious stone ornaments (particularly turquoise). Clothing shop with printed pants, embroidary shirt etc. Also rice paper products such as lanterns and calenders seem to be popular. You can find both Nepali and Tibetan crafts here since there are many Tibetans around.
What to pay: King of barganing pays less.
In a lot of shops you can buy this kind of art. Try to look carefuly, some artists are good some are not. It's difficult to get good information from a guide or someone else...
What to buy: Go for some self-painted stuff or an ancient work. Prices can differ a lot. I paid 75 USD for a really nice Kalachakra (50 x 50 cm).
For all your travel related information books, maps, route plan, wall posters try this shop. Prices are okey but you get quality stuffs.
What to buy: Travel related Maps, Books, Picture Post cards, etc.