Through August 15, shoppers do not have to pay the 5-percent state sales tax on school supplies and many clothing items.
One teacher said when she began teaching, she didn't have any textbooks, and many of her students didn't have the basics.
"I was right out of college. I did not have a lot of money myself. I had student loans. I was still paying off from university, and I would spend over a thousand dollars on my classroom," said Erin Matsukane.
"I've spent so much money on my classroom. And this year I've been so excited. I went shopping yesterday and Friday to buy supplies for my classroom," said Margaret Healy of St. Sylvester School.
Governor Quinn said Sunday that back-to-school is the biggest shopping season next to Christmas.