Billy earned $150 from a summer job to buy new clothes for school. He found several items he would like to buy, but is trying to decide if he has enough money to buy all the items he likes. He found two pairs of shorts for $20 each and four shorts with an average cost of $18 per shirt. He will have to pay 6.5% sales tax.If he buys all of the items, how much sales tax will he has to pay?