Zhang Jie did not have time to examine her newly obtained 10 yuan banknote before a young guy stopped her at the bank doors near Wangfujing and offered her 150 yuan (HK$171) for it.
A return of 15 times the initial investment may be a dream, but Ms Zhang turned down the offer.
'I don't see it as just money. I see it as an Olympic memory that can be kept for many years to come,' she said.
Ms Zhang's non-economic consideration might pay off because the market price for the 6 million souvenir banknotes could be much higher.
Reports said yesterday that the banknotes were selling for more than 200 yuan in Shanghai, and someone in Guangzhou had raised the bar to 400 yuan.
A Henan man was offering his bill for 1,500 yuan at the popular retail website, Taobao.com, and about 300 potential buyers had visited the page by last night.
Chu Xia, secretary of the China Association of Collectors, said the bill should have great value as a collector's item because of the limited supply and the Olympics theme.
The issue of the 10 yuan banknotes marks the third time the mainland has issued special commemorative bills, with the first released in 1999 for the 50th anniversary of the People's Republic and in 2000 to celebrate the new millennium.
Liu Yang, a Beijing-based expert, said the value of the 10 yuan banknote had the potential to rise to about 600 yuan based on the earlier releases.
But the price could rise even higher in the short term because of the extraordinary emotions fuelling the Olympic frenzy, Mr Liu said.