Illinois' back-to-school sales tax holiday begins this week, but unlike other states, it won't be the start of a tax-free weekend. WATCH HERE WATCH HEREThe back-to-school sales tax holiday, which gets underway on Aug. 7, waives Illinois’ 5% sales tax on school necessities through Aug. 16. During the 10-day holiday, consumers will pay a reduced sales tax rate on specific clothing and school-related items. That reduced rate drops the state’s portion of the sales tax from 6.25% to 1.25%, according to officials. At a news conference promoting the tax holiday on Monday, Gov.