Now through October 14th you can earn up to a 40% bonus on purchased Alaska Air miles. The bonuses are tiered:
Buy 5,000 – 19,000 miles, get a 20% Bonus (2.29 cents apiece)
Buy 20,000 – 34,000 miles, get a 30% Bonus (2.115 cents apiece)
Buy 35,000 – 40,000 miles, get a 40% Bonus (1.96 cents apiece)
Normally Alaska miles cost 2.75 cents apiece.
Is it worth it to buy them? Not speculatively. A couple of bloggers (One Mile At A Time, The Points Guy) who publish their point valuations rate these points at 1.8 to 2 cents apiece. So if you’re going to buy them without a current purpose, buy at least 35,000 miles. But if you only need a few miles to top off an award, it may very well be worth buying even a few thousand points.