Virginia’s annual back-to-school sales tax holiday is in full swing. The tax break started Friday and runs through Sunday. Shoppers at retail stores statewide won’t have to pay sales tax on notebooks, pens, calculators, binders and other school supplies priced up to $20. Shoes and most clothing items priced up to $100 also will be exempt. The Department of Taxation has a list of eligible items and guidelines on its website, http://www.tax.virginia.gov.