Alaska Airlines is offering up to a 50% bonus when you purchase or gift miles through June 13. You give them your name and account number and it’s revealed what bonus you’re eligible for. The 50% offer seems broadly available although I’ve seen reports of getting offered just 40%.
At 50% purchases are really tempting, and Alaska’s are the only airline miles I’d personally do that with. Other airlines take at least a 100% bonus. That’s because the starting price of Alaska’s miles is lower than many other airlines.