I would tend to buy a couple pieces of teaware everytime I am in China. I am fascinated by the porcelain teaware in the tea markets as the variety never fails to astound me.
Yes, there are very high quality collectors' porcelain teaware. You can find very intricate artwork on the porcelain or the finishing artwork will make your jaw drop to the ground. I saw a set of tea cups, handpainted with Chinese landscapes complete with beautiful Chinese calligraphy, whose thinness of the porcelain was like egg shells and it has a bewitching translucent quality when you hold the cup against a light. I did not buy this set as I tend to be accident prone when it comes to delicate porcelain. There are collectors who are fans of certain porcelain artistes and would buy every new series when its available. These range of porcelain are usually quite expensive.
The less expensive option for many tea drinkers would be to buy their teaware from the 'mass production range'. They are inexpensive and you can find a wide range of teaware that will appeal to you. The above pix are examples of teaware which are inexpensive and to me, very well made. I found the quality and finishing excellent and they make a tea drinking session more enjoyable (to me).
I must emphasize that in the wholesale tea markets of China, you will get a good price if you buy in bulk. The tea shops may sell you individual pieces but you may be paying a much higher price. One more thing, I tend to hand-carry these porcelain (which can be a pain) as these pieces, if packed in check-in luggage, may end up in several more pieces when you have reached your destination.