Not being online is costing the most vulnerable people in society, a campaign group has warned, with offline households spending £440 a year more for their goods and services than those who are connected.
Households without the internet spend the equivalent of 4.4% of their household income unnecessarily by being offline, rising to 5.4% for the over-65s.
The research, from the Centre for Economics and Business Research (CEBR), has revealed that the biggest average savings offline households miss out on are the discounts offered to energy and telecoms customers for buying online and switching to paperless billing.
Together, these account for around £139 a year. Typically, telecoms providers offer savings of around 30%, or £88 on average, to online customers. And energy companies offer a 6% discount, or £51 on average.
Other online savings those without the internet miss out on include 16% off package holidays and accommodation, 15% off TVs and computers and 10% off food.
While the number of people online has nearly doubled over the past 10 years - from 46% of the UK population in 2003 to 83% in 2013 - some 7 million people have never used the internet and 5 million of them are elderly or receiving benefits.
A recent report by the Nationwide Foundation and Sliced Bread highlighted the plight of vulnerable members of society unable to switch on an online customer account or paperless billing.
One household said: "Yeah, you get charged for paper bills. So if you haven't got a direct debit, for [cable services provider] it's like £2 [per month] for a paper bill... which, I know it's only £2, but it all adds up at the end of the day.
"When you've got five or six of them at £2, that's a weeks shopping when you're on benefits, you know."
Judith Donovan CBE, chair of the Keep Me Posted campaign, said: "It is clear that, whatever your household income, there is cost for those who manage their affairs 'offline', be that through choice or circumstance.
"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."