There are local product shops both in the scenic area and the the downtown area of Zhangjiejia. In the city center, Renmin Guangchang (People's Square) and Tianzi Jie are busy street for shopping. As to local products, you can buy Tujia brocade and painting, as well as some food. Do not buy stone, antique or Chinese herbal medecine unless you know them very well. Winter is not a very good season to see Zhangjiajie. Yes, it is getting cold since Dec. The temperature is about 5-10C, perhaps a bit warmer in early this month and in a sunny daytime. If it rains, it will be colder. Generally, it will not snow in Dec and it is safe. if the road condition is not that good to climb, take cableway or elevator. Enjoy~