By Candace Piette
BBC News, Buenos Aires
Everyone holds on to their small change fiercely in Buenos Aires
Argentina's president has announced a new electronic ticketing system for Buenos Aires' public transport to fight the capital's dire shortage of coins.
Cristina Fernandez de Kirchner said her government was investing some $57m (£39m) to end a black market in coins which had developed in recent years.
In Buenos Aires, one cannot use buses and trains without coins, and other services have run out of change.
The shortage of coins has also led to long queues at banks in the capital.
People wait patiently to swap a five or 10 peso note for a small stack of coins to use on public transport.
Last October, the government put into circulation millions of dollars in coinage but it did little to alleviate the shortage.
The country's central bank said at the time that coins were being illegally retained, after a security van was found filled with barrels of coins.
Street beggars affected
A black market has also sprung up where street vendors are selling coins, but charging between 3% and 10% more than the face value.
Small change could be a matter of life or death for the city's poor
When that was made illegal, street sellers started delivering coins in a mix of biscuits or sweets, making a fat profit.
As a result of all this, everyone holds on to their small change fiercely in Buenos Aires.
And in shops there is always a tussle between the sales person and the customer over rounding up or down the amount to get round the change issue.
And with few coins around, the street beggars have done little trade in recent months.
The government's move to an electronic ticketing system has been welcomed in the capital.