L.H.
Oil companies can be rather persnickety. Once you chose an oil company, you need to stay with it for a few years before changing again if needed. I find you're best to pick a "full service" oil company, so that you can have the oil burner/burners maintained properly and fixed when needed. You do need to shop around first to find the cheapest price. Here, it seems like it's always the same one with the cheapest price which was the company the original owner of our house used. (I checked.)I have also found that reliability is a key too. Some companies aren't very reliable when delivering oil the day they say they will. One company offered prepaided oil contracts, then went out of business and declared bankrupsy to try and get out of paying back the people who did the prepay contract. You'll want to read any prepay contracts you might be temped to sign, because some of them will not lower the price of the oil when it goes down sticking you with the higher amount you prepaid. Ours used to adjust the contracts to the lower rate, but not any more. You can also have automatic delivery, which means they will automatically show up at your house to fill the tank every month. We don't do that. It's convenient, but is a money waster for us in the long run since we don't use much oil in the summer and wouldn't have the opportunity to purchase the oil when it's lower in price. The price of oil fluctuates from day to day. Some companies want you to be there the first day they fill the tank and will only accept cash until you become a regular customer. Depending on how new or well insulated your house is and how cold the winters are, you may want to invest in some down blankets and learn how to temporarily seal leaks for the winter in order to save money.
Just noticed someone suggested to only half fill the tank....You have to be careful when you do this, if you have an older tank. Older tanks have silt in the bottom from years of various oil grades. If you get too low, you get too close to the silt and wind up with it getting into your burner and messing things up. You're better off to have it filled, then refill it when it gets half empty. Same concept, only safer.