It will cost just €103m to ensure that every primary school child gets a truly free education, according to charity Barnardos.
A campaign is being launched today to persuade the Government to find the funds to pay for primary schooling.
At the moment the parents of almost 550,000 primary school pupils are shelling out more than €100m between them every year to pay for books, school transport, provide voluntary contributions to the school, and fund classroom resources.
Barnardos wants the Government to guarantee free access to education for every child.
The Department of Education and Skills has a funding allocation of €8.8bn, according to its website.
Barnardos estimates, from surveys it publishes every September, that parents end up having to spend an average of €185 a year per child.
Setting aside €103.2m would fulfil the Government's Constitutional obligation to deliver free education, it argues.
Parents are under huge pressure to pay for stationery, bus passes, school books and voluntary contributions, Barnardos says.
This view is based on a number of surveys it has conducted over the past 10 years assessing the costs involved in education.
Chief executive of the charity Fergus Finlay said: "The current cost of education gets in the way of the best possible start for a child's life. That's why we're arguing that now is the time to make that final step.
"It's an investment in equality. It's an investment in opportunity.
"It's an investment in much better economic and social development for our country into the future. Now is the time."
Head of advocacy at Barnardos June Tinsley said children living in low-income households are most likely to be affected.
"By investing a tiny fraction of the Department of Education's overall budget, we could guarantee free primary and secondary education for all."
It costs parents of a fourth-class pupil on average €85 for books, €40 for classroom resources and €75 in voluntary contributions.
Parents also have to pay for uniforms and shoes, but Barnardos is not arguing that the State covers that cost for every child.
A further €126.9m - or €335 per student - would fund free secondary education and Barnardos is calling for that commitment to be made by 2018.
Around three-quarters of parents surveyed by Barnardos in its 'back to school' costs survey last year said they had to buy a uniform or tracksuit with a school crest, with many saying they wanted to be able to buy cheaper uniforms that didn't have logos.