That $1.29 iTunes song or $9.99 e-book may be more expensive than you think. If you live in one of the nearly 25 states that charge sales tax on digital goods or services you likely pay more for everything from downloaded music, e-books and ringtones to streaming TV shows and video. And a growing number of states are finding ways to tax our digital diversions. While some states rely on existing sales tax laws, more than a dozen have enacted sales tax laws specifically targeting digital goods. In July, Minnesota's residents will be the latest consumers to pay tax on...