Swapping unwanted items for useful ones is becoming a popular pastime in the city as more and more people become involved in online swap websites or go to real-life flea markets.

The famed Panjiayuan market holds a flea market every Monday to Friday and has attracted as many as 80,000 visitors a day to the 1,100 stalls, according to Beijing Evening News.

"(People reserve stall space at the market) to earn some money by selling their unused goods and that is good for those of us retirees who have nothing to do at home," said Pan Shaosong, 65, who often frequents the market.

But while many older people are increasingly enjoying the flea market as a way to buy and sell unwanted items, the younger generation is clicking online to buy, sell and swap.

Online, there are more than 60 websites offering a wide range of specialties - including books, kitchen supplies, gadgets, home appliances, furniture and more - according to Zhu Jie, a 26-year-old white-collar worker who is registered as a member of several such websites and who regularly does online swapping.

But people should be cautious about swapping because the industry is still not mature, according to Wei Xiaodong, a lawyer from Beijing Huiyuan Law Firm, who suggested people meet and swap for goods face-to-face in order to avoid being cheated.

"There are two things that people should pay attention to," Wei said. "The first is they should make clear that both sides can get an invoice from the other when they swap goods and the second is they had better check the quality of the goods in case they are cheated."

Unused goods available to be swapped in the city have now reached a value of 2.8 billion yuan, according to Beijing Evening News. And swapping is being seen as not only practical but part of a low-carbon lifestyle and a good way to manage wealth, according to the report.