When I was trained in as a cashier, one of my superiors made it clear that tabloids like WWN and NATIONAL ENQUIRER were tax exempt, yet magazines like TIME and NEWSWEEK were taxable. Uh…why?
WAG: WWN and its ilk are considered newspapers, and you live in a state where newspapers (but not magazines) are exempt from sales tax.
http://www.revenue.state.co.us/fyi/html/sales44.html
(That’s the law in Colorado; YMMV)