You can put this solution on YOUR website! $720 is original.
What does it mean to be 15% off?
It means that we paid (1-.15) = .85 of the original.
Before sales tax but after discount we get 720 * .85 = $612.
We go to check out and sales tax is applied. This means that we now pay 106% of the price, or 1.06.
612 * 1.06 = $648.72 ... expensive i-pod!
Hope this helps!