Many national pavilions have cancelled passport-stamping services because of people like Willen121, who create problems at queues waiting for stamps. However, pavilions are now starting to resume stamping services using volunteers provided by Expo organizers.

Willen121 said he needed to collect more than 100 stamps for each passport to sell them for 260 yuan each.

While having the opportunity to enter the Expo Garden at will is required for those in the passport stamp business, others who do not have this privilege have turned to other means to make some money. Liu Fangchi is one of those. He owns dry cleaning and laundry shop close to Gate 2 in Puxi section of the Expo Garden.

Since early June, Liu has diversified his business by selling foldable stools, umbrellas and slippers, which he has displayed in front of his shop to catch the Expo crowds as they pass.

"All of these things are necessities in the Expo Garden in summer and they are in great demand," said Liu, adding sells about 10 stools - a steady business but not as good as street vendors selling the same products.

The foldable stool has become ubiquitous in the Expo Garden. It has become a necessity for a respite from all the hours of walking that visiting the Expo entails. And vendors selling this product are cleaning up, with some reportedly raking monthly profits of 6,000 yuan.

Earning money, however, was only part of the reason 40-year-old Li Song started his Expo business. He was among the first locals in the city to offer rooms for rent in their homes to Expo visitors.