Through April 15, 2012, Alaska is offering up to a 40% bonus on the purchase of Mileage Plan miles, with the following bonuses:
Alaska miles ordinarily cost 2.75 cents each plus a 7.5% federal excise tax, for a total of ~2.96 cents each. You can purchase up to 40,000 miles per transaction, so through this promotion you’re looking at a maximum of 56,000 miles (40,000 purchased miles plus 16,000 bonus miles) for $1,100, plus the federal excise tax, for a total of $1,182.50 .When you crunch the numbers on that, it comes out to ~2.1 cents per mile.
It’s not necessarily a price at which I’d stock up just for giggles, though this is about as good of a bonus as I’ve seen.
Alaska has some absolute gems on their award chart, including 140,000 miles for Cathay Pacific first class from the US to Asia, South Africa, India, and the Middle East (that’s up to four longhaul flights in first class on a single award). So if purchasing miles would put you over the top for one of those awards, I’d certainly consider taking advantage of this promotion.
(Tip of the hat to Gary)