The second Sunday of August to the following Saturday is designated as Shop Maryland Tax-Free Week each year. That means qualifying apparel and footwear $100 or less, per item, are exempt from the state sales tax. This year, the first $40 of a backpack or bookbag purchase is also tax-free. Accessory items, except for backpacks, are not included. The Shop Maryland Tax-Free Week for 2017 is Sunday, August 13 - Saturday, August 19.
You can find more information on the Comptroller of Maryland web page.