(Crain’s) — Gov. Pat Quinn on Wednesday signed a law to exempt certain purchases in August from state sales tax — an effort, he says, to provide some economic relief to Illinois families. The legislation — Senate Bill 3658 — marks the first time the state has instituted a sales tax holiday. It will take place Aug. 6-15 and apply only to some back-to-school items. The exemption does not apply to computers, related items such as ink and flash drives, or items required for after-school activities.