Students and the tea shop
This scam usually involves 2/3 young people (students). With the excuse of wanting to improve their English, they take you to a nearby tea shop where you sample different types of tea and traditional sweets. The surprise comes with the bill, which can cost up to 3,000 and 4,000 yuan.
This scam occurs especially around Tian'anmen Square, mainly at the gateway to the Forbidden City. You can avoid this by simply asking them to talk in a bank or public space if they plan to con you they won't want to.
Illegal taxi drivers
Although there aren't many in Beijing, only use the marked taxis. If you take an illegal one the meter will go up too high or it simply won't have a meter and you'll pay an exaggerated price. Illegal taxi drivers tend to wait at the airport and as you pass the baggage claim hall they'll offer you their service. Pay no attention to them and continue to the taxi stand, where the labelled taxis are waiting.
Sometimes rickshaw drivers invent distances to sell their services. For example, when you leave the subway station next to the Temple of Heaven, you'll be told that the Temple is in another direction, very far away. If you walk in the opposite direction you'll find the entrance 20 metres away.
It's also possible to find people at the entrance of well-known restaurants who might tell you that the place is full or closed and recommend an alternative. Ignore it and find out for yourself.
Although there are fewer counterfeit notes in circulation, in China they'll always check the validity of the notes when you pay them. If you suspect that you may have been given a false note, touch Mao's shoulder, the ink must make small grooves.
The Art Gallery
While this can't be considered a scam, it's a risk to be in a compromising situation. It consists of someone telling you that there is an art exhibition by a friend, family member or acquaintance, once they take you there they'll do their best to get you to buy a painting.