Crude oil prices opened slightly lower Tuesday on the New York Mercantile Exchange. The price for a barrel of crude opened at $102.44, down slightly from Monday\'s closing price of $102.55. Natural gas prices opened at $4.190 per million British thermal units, up from the settlement price of $4.154. Home heating oil was flat at the opening of the NYMEX trading day, selling for $2.9618 a gallon, the same price as its settlement price Monday. Gasoline began the trading session at $3.2955, off from the prior price of $3.2784. At the pump, the price for a gallon of regular unleaded gasoline was $3.951 Tuesday, down from $3.960 Monday.