Crude-oil prices sank below $50 a barrel, and the average cost of a gallon of gasoline at the pump hovered just above $2, a free fall in prices that is reverberating through the economy.

The sudden reversal -- the fastest and sharpest since 1980, when the government began tracking monthly gasoline prices -- is bringing relief to some and complicating business for others. Tumbling energy prices led October's 1% decline in consumer prices, deepening concerns about a long recession.

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