The second Missouri sales tax holiday is set to get underway Friday, and Governor Matt Blunt is encouraging shoppers to head to the stores to spend money. Blunt says the economy benefits because many of the people who buy tax exempt goods end up purchasing taxed items, as well. He says, however, the biggest beneficiaries are parents who can save some money dressing their kids. The 4.225-percent state sales tax is waived, this weekend, on most school supplies and items of clothing, and many computers. Local sales taxes will be charged, however, in cities and counties which have opted out of the sales tax holiday.