Parents again will be able to take advantage of a back-to-school tax holiday this weekend.Necessary school supplies will be exempt from state and local sales and use taxes for 48 hours on Friday and Saturday. Back-to-school items that are exempt from sales tax include clothing under $100 per item, general school supplies and personal computers and accessories under $1,000.This will be the first tax holiday for school items since the popular event was canceled at the start of the 2010 school year for economic reasons.While shoppers seem to be glad for the break on the necessary items, most agree the timing is a little off. Hall County and Gainesville City schools start class on Friday as well.