In the summer you'll see oil companies advertising that they're signing customers for their "budget payment plan". You can do the comparison shopping then between companies that deliver to your area, but the prices are for a limited time. After the opportunity passes, you pay full price for the oil. If you move to a house you've never lived in before they'll visit if they can and look things over. If they can't visit, they'll ask you questions over the phone about the house. You'll be asked how much oil the house used the previous winter. In many small towns, the oil company all ready knows the house and who lived there, and chances are good they delivered there! lol....the whole thing may sound daunting, but once you're in with a company they send you remind notes that it's time to "renew" and if you forget, they'll probably call you and give you one last chance--at least in small town Maine

Or, the secretary who works at the oil company sees you in the grocery store, asks you about it, and signs you up the next day

Lots of business gets done "informally"
