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.

Regardless of the offer you’re targeted for you will be presented with a tiered bonus. For the 50% offer, it’s:

With this offer you can buy 60,000 miles, receive 90,000, at a cost of $1773.75 or about 1.97 cents per mile.

Key things to know:

• You can make as many transactions as you like — there’s no limit to the number of miles that Alaska will sell you, or to the number of bonus miles you can earn with this promotion. But you can only use the same credit card up to 4 times per 30 day period for any Points.com transactions, so if you’re going hog wild you’ll need to spread the purchases across multiple cards.

• Since the transactions are processed by points.com, not the airline, these purchases aren’t treated as airfare by credit card companies and as a result don’t earn airfare bonuses.

It’s great that you can buy enough miles for an award from scratch, although Alaska doesn’t hold award tickets and let you buy the miles later. You’d have to find availability, buy miles, and go back to ticket… or work with a phone agent to set up a reservation while you try their patience and complete the mileage purchases online.

I really like Alaska Airlines miles because they offer one-way awards on nearly all of their partners and most booking functionality is available on their website. One way awards allow an enroute stopover. So booking roundtrip allows two stopovers in addition to your destination.

Alaska partners with many of the airlines both in oneworld (like American, Cathay Pacific, Qantas, LAN) and Skyteam (like Delta, Air France, Korean) and also non-alliance airlines like Emirates. You cannot book first class awards on either Air France or Korean (business is the highest cabin offered).

Alaska miles are somewhat less appealing since they devalued their Emirates awards without notice a month ago. They even went so far as to offer to refund mileage purchases made in March over the debacle. It’s sort of special that they blamed people buying their miles they were selling for the devaluation, and to come right back with the biggest bonus on mileage sales they offer.

Cathay Pacific first class inventory is also tighter than it used to be although they still reliably make unsold first class seats available close to departure.

Of course they also have unique partnerships like Hainan Airlines whose award availability tends to be quite good and also Icelandair.

However I’m not in favor of hoarding miles at these prices. Or hoarding Alaska miles at all. Especially now that we know their policy is to give only 30 days’ notice of changes, and even then only sometimes. That simply makes them not trustworthy in my view.

But it’s strategically useful and I’ve purchased Alaska miles with even a 40% bonus. If you have an immediate or very near-term use for the miles, this good be a worthwhile offer.

And I’m still waiting for someone to claim the taxes back from mileage purchases because they redeem the miles for international travel rather than domestic…

(HT: Frequent Flyer Bonuses and One Mile at a Time)