Householders who stay offline are losing out by between €300 and €400 a year as the best deals are reserved for those who use websites.
It costs more for banking, utility bills, TV and broadband bundles if they are bought the traditional way.
And it costs heavily to have a bill posted out to a home. Some companies are charging up to €40 a year to send out paper bills every month. This means that companies are profiteering from people who don't have the skills or cannot afford to be online.
New research, commissioned by the Irish Independent, shows companies offer discounts of up to 12pc to those prepared to transaction through a website rather than engaging with a company employee.
This translates into savings of €60 a year on typical household bills like energy and car insurance.
The high cost of signing up for goods and services without using an online facilities particularly hits older people as fewer of them tend to go online to buy services and goods.
And lack of broadband in many rural areas means almost one million people are in a situation of digital exclusion and these people are shut out from the best deals.
Simon Moynihan of comparison site Bonkers.ie said: "There is definitely a postal premium being paid by householders that stay offline, and each year it becomes more expensive to manage your affairs with a pen and paper."
He totalled up the costs and estimated that a typical household that avoids getting deals online is losing out to the tune of around €330 a year.
"It's car insurance season, and if you don't look at renewing online you're losing out. Insurance companies are now offering online discounts and cash incentives that could easily save you 10pc on your premium. That's about €60 for a regular family car."
Mr Moynihan said most mobile phone operators offer discounts to customers that sign up online. Meteor is currently offering 20pc off some plans which could save €120 a year.
"Still getting a paper statement from your energy company? It could be costing you a fiver a month or €60 per year," he said.
The cost of sending a cheque a week can work out at €45 a year for AIB customers. This is made up of 50c stamp duty imposed by the exchequer, and cheque processing fees of 39c. This excludes the 68c cost of a stamp, Mr Moynihan said.
This means every cheque you write could be costing up to €1.57 each.
Some customers of TV services are paying more than €40 a year to get their bills in the post. And the research shows that it does not pay to prepay for your energy.
Customers that opt for voluntary prepayment electricity meters from companies like PrePayPower will pay a special €137 "prepayment service charge" on top of Ireland's highest unit rates, Mr Moynihan said.
"An average household is paying over €300 a year more than they need to by having a prepayment meter," he said. Banks also penalise those who do paper-based transactions in branches.