She spent 16.49 dollars for 3 magazines and 4 sheet of stickers.
 => magazine costs = 3.99 each
 => tax costs = 1.02
 => coupon = 1.50 off her purchase.
 Solve for the cost of each stickers.
 => 39 * 3 = 11.97
 => 16.49 – 11.97
 => 4.52 + 1.02 (tax amount)
 => 5.54 – 1.50 for the coupon
 => 4.04.
 Let’s divide this by 4 sheets of stickers
 => 4.04 / 4 
 => 1.01
 The price of each sticker is 1.01