Illinois back-to-school sales tax holiday starts Friday August 7th and runs through Sunday, Aug. 16. Over those 10 days, state sales tax on qualifying items will drop by 5% -- from 6.25% to 1.25%. JB Pritzker, the sales tax holiday is expected to save Illinois families up to $10 million in school supplies. Here's a breakdown of what's eligible and what's not, and what else to know about the sales tax holiday:Which items are part of the sales tax holiday? Under provisions of the state law, most school supplies like rulers, notebooks, pens, pencils, crayons and other items will qualify.