People who cannot access the web face shelling out £440 more a year than those who shop around using the internet or make the most of online-only services such as lower energy and telecoms tariffs.
The Centre for Economics and Business Research, which carried out the survey, said the extra cost represented 4.4 per cent of the average household income, rising to 5.4 per cent of the poorest people, typically the elderly and vulnerable.
Internet access has improved in recent years, with the number of users increasing from 46 per cent of the population in 2003 to 83 per cent last year. But there are still seven million people who have never used the internet, including an estimated five million who are thought to be elderly or vulnerable.
The Keep Me Posted campaign, which is calling on organisations to protect customers' rights to choose paper bills and ensure there is no charge for that service, commissioned the study.
Its chairwoman, Judith Donovan, said: "Much progress has been made in ensuring that as many of us as possible can access the internet and the economic and social benefits it undoubtedly offers. However, the digital divide remains a big problem.
"A significant number of people have never, and probably will never, access the internet. Yet this is where the impact on household budgets is the greatest. For example, the elderly and most disadvantaged in our society are typically out of pocket by around 5 per cent of their household income."
The research found that almost three-quarters (72 per cent) of those who had never used the internet were in the lowest household income band, receiving £128 or less each week. They were unable to take advantage of potential savings of around £139 a year on their energy and telecoms tariffs.
People who shop around online can also save up to 30 per cent, equivalent to an average of £88, when buying communications products.
Ms Donovan said: "It is clear that there is cost for those who manage their affairs 'offline'.
"The Keep Me Posted campaign is calling on service providers to give their customers the choice of receiving their bills and statements on paper at no extra charge."