The market average propane price per gallon in the state of Oklahoma is available online through the U.S. Energy Information Administration. Data is collected weekly from March through October; and consumers can call around for the most competitive rates during other times of the year.
The propane market is a competitive one where each individual company ultimately establishes the price, explains the Marketing and Safety Commission of Oklahoma LP Gas Research. Some companies include products and services to customers with the purchase of propane, typically resulting in steeper prices, while others have additional charges for tank leasing, minimum usage, delivery charges and other extras.
Bulk propane is priced by the gallon and handled and stored as a liquid, which is then pumped into the customer's container through a flow meter or other approved measuring device. Portable propane cylinders are typically filled by weight, with the price of the gas figured by the pound. The liquid propane is weighed on approved scales as the cylinder is filled; approximately 1 liquid gallon propane weighs roughly 4.24 pounds.
Propane may also be priced by the cubic foot. In such instances, a vapor meter is installed to gauge propane as it is consumed, with 1 gallon propane equal to approximately 36 cubic feet.