This year, Maryland will hold its tax-free week starting Sunday August 12 to Saturday the18th. The Comptroller's information sheet goes into great detail about how the sales work, but generally any clothing or footwear item that costs less than $100 is tax exempt, which means they are suspending the 6% sales tax and any local (county) tax that may be in effect.
They also post a handy -- and exact -- list of qualifying items.
Beware -- check prices across retailers, because some have reportedly jacked up prices a bit to cover taxes anyway. You might do better shopping the week before or after. But my money's on after, or late in the week.