45% off of a $83 phone
$40 rebate on a $83 phone
what coupon gives the lower price.
45% off means that the cost of the phone is 55% of its original price....so
55% * 83 = .55 * 83 = $ 45.65
$40 rebate means the cost is 83 - 40 = $43
The rebate is the better deal