Huseyin Uysal flicked through a thick wad of Turkish lira, the earnings of his travel agency for the day.
'Every evening we have to take all this to the bank and convert it to US dollars. Many companies do this. No-one knows how much the lira will be worth tomorrow morning.'
In one of the worst financial crises in the 78 years of the Turkish republic, the lira has lost more than 40 per cent of its value since a public row between the country's president and prime minister on February 20. One US dollar now buys about one million lira.
'What everyone does is save dollars and spend lira,' said Mr Uysal.
'You keep your money in dollars, marks or sterling and, when you need to buy something, change the amount of lira you need.'
That means big business for the money changers who offer more attractive rates than the banks.
One of them is a few doors down the street from Mr Uysal's travel agency in the old quarter of Istanbul - a plump man and a woman with heavy make-up behind a glass screen with calculators and steel cabinets full of money, guarded by a sinister-looking man who puffs a cigarette and tosses nuts into his mouth, while he scours the street for unwanted visitors.
On the wall is an electronic screen with buy and sell prices for all the currencies of Europe as well as the yen, the Hong Kong dollar and Korean won. One man comes in to exchange US$50, another just one.
'They can change US$100,000 in 10 minutes,' said Mr Uysal.
'That needs a visit to the nearby Grand Bazaar, the city's biggest market.'
On the street outside are the victims of the crisis - pedlars, shoe-shine boys, old women beggars and dozens of men with a thick stubble smoking cigarettes and waiting in vain for work. Bakers find a ready market for bread that is one-day-old.
In recent weeks, the value of the lira has followed the efforts of new Economics Minister Kemal Dervis to secure a loan package worth US$10 billion from the International Monetary Fund. It would be the 18th rescue package for Turkey in 40 years.
Because of the instability of the lira, prices for big-ticket items such as cars, personal computers, office rents and house purchases, are often quoted in US dollars.
Mr Uysal is one of the lucky ones, because tourism, one of Turkey's main foreign exchange earners, should benefit greatly from the devaluation.
But it is a disaster for the majority of urban people who earn a fixed monthly salary in lira that has not increased, such as teachers and civil servants, and have seen the prices of the goods they buy shoot up.
'Before the crisis, I sold 150 mobile phones a month,' said Gurkan Berkoglu, 25, who works for Aria, an Italian company that was last year given the third mobile licence in Turkey.
'Now I sell 20 to 25. My boss gives us a lunch voucher instead of pay and wants to cut our salary because he knows it is hard for us to find other jobs. So far I have persuaded him not to.
'Aria imports its phones and is spending heavily to build its own transmission system, with equipment that is imported. So its costs are going up in lira terms.
'Worst hit in this crisis are pensioners on fixed incomes like my father, a retired factory worker. He has had no holiday for six years and has to stay at home most of the time.'
Like many young people, Mr Berkoglu is considering study abroad. He has a sister and brother-in-law living in Zurich, where he may go for an MBA.
'A survey of students between 20 and 30 found that 70 per cent want to go abroad. They have lost confidence in our corrupt politicians,' he said.
'We are 20 to 30 years behind Europe. Our social welfare is bad. If you have money, you can buy good medical care. Otherwise, you are in trouble.'
Baris Atayman, 20, a marketing student, said that when he was a child there were five-, 10- and 50-lira coins.
'When I was 10, I could buy two Cokes for 50 lira. Now it costs me 600,000.
'My mother lost her perfumery shop during the last devaluation in 1994, when the lira went from 9,000 to 36,000 to the dollar in one day. She was forced into bankruptcy in two months by her debts.'
This crisis too has put thousands of small traders out of business.
They have held violent demonstrations against the government in several cities.
In the largest, in the capital Ankara, one businessman threw his cash register at Prime Minister Bulent Ecevit, a television image that went round the world.
For Mehmet Hasimi, who drives cars for a rental firm, the crisis has only increased his determination to return to the country where he spent the first 16 years of his life - Germany.
'I curse the day that my parents decided to come home after 30 years,' he said.
'I was 16 and had to return with him, while my brother and his wife, both Turkish, were older and able to stay. They took German citizenship last year.
'I have tried repeatedly to get a visa to go back but have always been refused.
'Turkey is a very good country but you cannot earn money here. A 40-year-old German spinster has offered a fake marriage with me for 20,000 Deutschemark (about HK$79,300).
'To get a passport, I would have to stay with her for five years, when police can conduct a raid at any time to see if you are really living together.
'It would be very hard and I would have to divorce my wife here.
'But I am determined to go.'
In one demonstration a businessman threw his cash register at Prime Minister Bulent Ecevit