We live in the country and have a 1000 gallon propane tank we use to heat our house and garage. We have living quarters above our garage, so we keep this area heated all winter long as well as the house.
Depending on how cold the winter is, we can go through quite a bit of propane. We usually contract a certain amount of gallons to use every year based on what we have used in the past.
This way we get the best cost and don't have to worry if the price of propane gets extremely high during a cold winter.
I make sure and check our propane tank gauge every so often to see how we are doing on fuel. They charge a delivery fee every time they come, so I don't like to call them too often, but I also don't want to run out of propane.
We also pay a fee every year for the tank rental. This propane tank was here when we bought the property, so we use the same fuel service as the previous people who lived here did.
I don't know how much it would cost to buy our own propane tank, but I imagine they wouldn't be very cheap.