The government's unorthodox approach to solving the country's runaway inflationary spiral met with skepticism from critics who say the order is ill-conceived. At least 300 essential commodities and products are affected.
Fernandez aides said they want supermarkets to offer a basket of 300 basic products at lower prices as part of the effort to fight inflation.
Labor disputes sparked more unrest in the capital and other cities amid continuing demands for higher wages and protests over the government's fiscal and monetary policies.
Official statistics indicate Argentina's inflation at no more than 10 percent while independent figures say annual inflation calculated in August is above 24 percent.
Argentine growth this year is also being affected by the government's stringent curbs on imports that have affected productivity in many businesses.
The government's latest forecast put economic growth at 3.4 percent this year, down from 8.9 percent in 2011. Critics dispute both figures, however.
Argentina's official economic statistics have drawn criticism from independent financial and international data gatherers, including the International Monetary Fund.
The IMF stepped into the debate last month and gave Argentina until mid-December to improve the quality of the gross domestic product and inflation data it reports to the fund or face sanctions.
Wage protests and the government's response to them cast doubt on the government's handling of the various labor disputes.
This week thousands of troops and petty officers from the border patrol and coast guard and some naval and police sectors went on strike over wage cuts and working conditions.
Fernandez responded by firing the coast guard and gendarmerie chiefs and forcibly retiring their 10 commanders. Senior aides later announced the situation in the security forces was normalized after the reshuffles.
A recent government decree eliminated all extra compensations and benefits in the forces, leading to pay cuts of up to 70 percent for some staff.
Protesters are demanding the elimination of the decree and significant increases in basic salaries.
Protesters in central Buenos Aires said the security personnel were "workers like any others who need to support our families."
The protesters want the government to participate in realistic negotiations to resolve the wage disputes. So far the government has not indicated if it will take part in any negotiations to discuss the security forces' wages.