The average cost for a fourth class pupil is now 320 euro, compared to 863 euro for a fifth year student.
Barnardos is calling for the free book scheme to be extended to secondary school students.
The charity's Back to School Survey for 2023 has found half of primary school parents and two-thirds at second level, are worried about the cost of sending their child to school this autumn.
It claims there's a direct correlation betwen the introduction of free schoolbooks for primary pupils and the reduction in back to school costs this year.
The average cost for a fourth class pupil is now 320 euro, compared to 863 euro for a fifth year student.
CEO of Barnardos, Suzanne Connolly says there are practical steps that can be taken: