Interesting and Inexpensive

Walk east along the Second Ring Road from the north exit of Jishuitan on line 2. You may pass several buses, taxis, and street vendors serving the Badaling-bound tourists in the area. Navigate the labyrinth of obstacles to the (south) entrance of the watchtower at Deshengmen (得胜门). Admission is 20元 for adults and 10元 for children. An audio guide costs 10元 plus a 100元 deposit that they return to you. I think the languages offered are Chinese, Japanese, French, English, and perhaps others. There are two exhibition halls showcasing about 4,000 years of monetary history from shells to sycees and coins to cash. There is a gift shop with reasonably priced souvenirs and you can ascend the watchtower (featuring cannons and other weaponry) to boot. Photography of the exhibits is not allowed, but the curators are approachable and seemingly interested in explaining and answering questions about the exhibits (in Chinese). I would recommend this outing to anyone interested in Chinese history, economy, banking, money, numismatics, etc.