Store clerks across North Texas are now catching their breath after a break-neck pace over the weekend, the Texas Tax Free weekend.  With the opening of school just hours away, shoppers by the thousands braved the jam-packed parking lots and just as as crowded aisles, hoping to save the state’s eight-percent sales tax on many back-to-school items, including clothing and school supplies.  Shopping malls from The Parks in Arlington to Grapevine Mills, along with large retailers like Target and Wal-Mart, all staffed up to handle the expected crush of bargain-hunters.  By waiving the sales tax, the state forfeits eight dollars in revenue for every 100-dollars in merchandise.