If you’ve been waiting for just the right time to get your back to school shopping done, this weekend would be it.

Friday through Sunday has been designated by state law as the annual back to school sales tax holiday.

According to the Missouri Department of Revenue, certain back to school purchases, such as clothing, school supplies, computers and other items defined by state law, are exempt from sales tax for this weekend only.

A number of cities around the state have opted out of taking part in the sales tax holiday. In northeast Missouri, the cities of Canton, Palmyra, Paris, Shelbina and Vandalia will still charge city sales tax on back to school purchases.

Also, the northeast Missouri counties of Audrain, Pike and Shelby will still charge county sales tax for purchases on back to school items this Friday through Sunday.