Bought my son an Apple laptop computer for college doing all his notes in class as well as everything else. Last year he had to buy Microsoft software to be able to Powerpoint, Excel spreadsheets, etc. I am pretty sure last year I paid 79 dollars for it, although he got it himself. He just this week a year later was charged another 79 dollars for the product again. Is this a rental agreement, or does Microsoft charge Mac users each and every year to have that on their laptops? Makes no sense to me, appreciate any help. Thanks.