Wendy Zhang/ Shanghai Daily news 

Various year-end promotions offered by local department stores and shopping malls have brought chances for scalpers to make money, eastday.com reported today.
"There are more promotions this year, involving offering discounts, coupons and gifts. Many stores offer 100 yuan (US$12) coupons for each 200 yuan of purchases. As we can sell such coupons to scalpers at a discount, we have to do swift calculations, which makes me dizzy," said a shopper who had done battle at a shopping mall for nearly seven hours, adding that she has to calculate how to make full use of each coupon and how to make a good deal with the scalpers at the same time.
"I want to buy a pair of 318-yuan trousers and can get a 100 yuan coupon. If I sell the coupon to the scalper for 70 yuan, then actually I only need to pay 248 yuan for my trousers. However, if I buy three 100-yuan coupons from a scalper at 75 yuan each, my trousers will cost 243 yuan, saving me five yuan," the shopper explained.
"However, just as scalpers often change the prices of their coupons, so we should do more calculations before purchasing," she suggested.
One of the purposes of promotions is to make consumers feel happy in their shopping, but scalpers have had a negative impact on the promotions, an industry analyst said.