In mid-November American offered a purchase miles bonus through November 30 that I thought was a bit disingenuous to tie to ‘Cyber Monday’.

It was still a good deal as far as purchase miles bonuses go, just not credible to call a “second half of November sale” a Cyber Monday deal.

I’m even more convinced of that now that American has extended the offer through January 4 — where they will continue to sell miles for as little as 2 cent apiece.

American AAdvantage regularly now runs purchase miles bonuses, and the price is often only marginally more than this. (Here was their offer from May, from July, and from October.)

Nonetheless, here’s how the offer works: Buying exactly 100,000 or 125,000 miles earns a 60% bonus. The bonuses are awarded in tiers based on ranges of miles that you purchase. Any amount other than 100,000 or 125,000 earns what amounts to a lower percentage offer.

Buying 200,000 miles costs $3994.06 (though you may be able to get the tax refunded).

That’s 1.99703 cents per mile. Let’s call it 2 cents a mile. That’s a good deal on American AAdvantage miles as far as it goes, most mileage sales that AAdvantage offer ~ 2.1 cents a mile at best. US Airways stopped selling miles at 1.88 cents apiece last fall. But American has been more aggressive selling miles than they were pre-merger.

One change though since the merger is that unlike US Airways, American processes these transactions themselves. As a result purchases count as bonusable spend for credit cards that give extra miles for airline purchases. (US Airways sold miles via Points.com, who processed the transactions.)

Noentheless, this is not a price at which I’m a buyer of miles. On average I value American miles at 1.7 cents. I may revise that downward a bit with the changes coming to American’s award chart March 22.

Of course the miles are worth more than that if they put you over the top for a specific award. And they’re worth more if you redeem them for something you’d be willing to pay full or close to full price for otherwise.

Incremental American miles are worth less than that to me because I have a large 7 figure balance of AAdvantage miles already. More miles are worth less at the margin because I won’t likely use any that I add to my account any time in the near future, let alone by the March 22 changes that affect me the most since I tend to redeem for international first class awards.

Real value is possible though:

• American allows you to put awards on hold for 5 days. So you can secure award space before buying miles.

• Business class between the US and Southeast Asia is just 110,000 miles roundtrip. Business class between the US and Europe is just 100,000 miles roundtrip (with fuel surcharges if you fly British Airways, so focus on Iberia or airberlin availability). It can make sense to buy miles for an award that’s currently available (although substantial advance purchase business class to Europe during off peak times can be less than $2000 paid).

Cathay Pacific first class is still 67,500 miles one-way between the US and South Asia

Etihad First Apartment is 90,000 miles one-way US to Middle East (or beyond to the Indian Subcontinent) until March 22

This isn’t something everyone should jump on. But some people will find it a worthwhile bonus.