More than a dozen states and the District of Columbia have sales tax holidays that last at least a couple of days each year, some last much longer. Usually the holiday coincides with back-to-school time to give parents a break on outfitting their kids with necessities. What consumers can buy during the sales tax holidays varies by state, but generally includes clothing, shoes, classroom supplies, and computers, often with a dollar limit. Another popular item that pops up in sales tax holidays is energy efficient appliances for the home.