There's no set price for a gallon of heating oil since the price of heating oil varies from location to location and it goes up and down in price all the time just like gasoline does.
But in most places if you buy a 1,000 gallons or more at one time it usually costs $1.98 per gallon of heating oil but it can be as high as $3.59 per gallon of heating oil in some locations and during certain times.
Home heating oil fluctuates wildly and can go up or down at anytime.