If you read th fine print, you can buy up to 60,000 miles per year (bonus miles do not count towards this total) and you may do multiple transactions. So, you could buy 30,000 miles, get the 8,250 bonus miles and then do it again. Total bonus would then be 16,500 against a purchase of 60,000, so 27.5%. Of course, you have to pay an extra $35 fee. But the total comes out to .0206 cents per mile, all in.