POWAY  (AP) — The American Civil Liberties Union is challenging a San Diego County school's project to equip fourth- and fifth-graders with iPads — at parents' expense.

ACLU lawyer David Loy has complained to Poway Unified School District, saying Tierra Bonita Elementary School's request that 90 percent of parents buy, rent or lease a $483 iPad and accessories veers close to violating the state Constitution guarantee of a free public education for all children.

"They exert significant pressure on families to either provide or pay for a digital device," Loy wrote in a letter to the district. "This pressure is dangerously close if not tantamount to directly charging an illegal fee."

Poway Superintendent John Collins said in a statement that he plans to meet with the ACLU to discuss the matter.

"Poway Unified has worked with Mr. Loy and the ACLU before, appreciates their input and looks forward to working with them on this matter as well," Collins said.

The school and its educational foundation, which raises money for school activities, are trying to launch a technology program.

Students have the option to use their own iPad or other tablet, buy one from the district at a cost of $379, plus a $79 warranty and a $25 case, rent one for $53 a month, or borrow one from the district.

However, it has warned that only 10 percent of children can borrow a device.

The ACLU has previously taken issue with school districts over charging fees for items ranging from textbooks to extracurricular activities. Districts say dwindling state funding forces them to ask parents to shoulder some costs, but the ACLU has warned that such fees are illegal.