(CNN) -- Amy Larcinese doesn't know who the man is, the one who walked into her elementary school and paid off the outstanding lunch bills of more than 40 students.

But the Secret Santa has brought relief to many struggling families.

Larcinese is the principal H.W. Good Elementary in western Pennsylvania. Nearly half the kids at the school are from financially struggling families and who qualify for free and reduced school lunches.

Like at other public schools, students who don't quality for free lunches have accounts where parents put in money every month. But sometimes -- especially around this time of the year when household expenses rise -- some of those accounts go into the red.

On Wednesday, a man came in through the school doors and wrote a check for $864 to wipe off all those overdue amounts. He then offered to provide funds to cover one child's lunch for the rest of the school year.

"This time of year can be a financial burden," Janet Sardon, superintendent of the Yough School District, told CNN. "His intent was to relieve that burden a little bit."

The school is drafting letters to send as a surprise to the students' families. The letters won't reveal who paid the tabs.

But school officials are grateful for the Secret Santa.

"Thank you so much for making a difference in the lives of our students," Sardon said.