"Buying and selling coupons illegally was common. People even bought and sold train and bus tickets etc. If you queued and couldn't get the ticket or you didn't want to queue, you could buy a"black market" ticket. The real price of a ticket was 5 hao(10 hao equivalent 1Vnd), you had to pay 7 hao. Illegally traders made a connection with the government clerks who sold the tickets," said by Mr Le Gia Thuy, aged 65, sub alley 12/21, alley 12 Luong Khanh Thien street Ha Noi.
This man's story reminds me of the time when I had to go to buy two train tickets for my relative with my sister. We had to queue for most of the morning at the station but we couldn't get the tickets so we were forced to get 2 tickets from "black market" traders. We pay 3 hao (about 50,000VND/US$3.20 in today's money, I guess) more than the official price but we decided to do that in future to save time.