There are several mileage bonus offers happening right now, but none of them are really amazing deals. Let’s take a look at each:AmericanAAdavantage members can purchase miles now through February 29, 2012 at up to a 37% bonus.The increments are:Purchased Miles Bonus Miles-2,000-5,000 miles 500 bonus-6,000-11,000 miles 2,000 bonus-12,000-39,000 miles 4,000 bonus-40,000+ miles 15,000 bonusSo, is it worth it?The short answer is: no. Let’s take the baseline examples though to price it out.American Airlines normally charges 2.95 cents per mile. In terms of this promotion, if you were buying 2,000 miles, you’d get a total of 2,500 miles for $59. That equates to 2.36 cents per mile - still not good.If you bought 6,000 miles for $165 (the normal price), you’d get a total of 8,000 miles at a cost of 2.06 cent per mile. Better, but still likely a losing proposition for most people.For a 12,000-mile purchase, you’d pay $330 and get a total of 16,000 miles. Cost per mile: 2.06 cents. Same as above.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.Finally, if you purchased 40,000 miles at the cost of $1,100 and received the full bonus of 15,000 miles, your cost per mile breakdown would be an even 2 cents per mile. This isn’t amazing, but if you are spending 100,000 miles for a roundtrip business class ticket to Europe that you would have paid more then $2,000 for, buying miles at 2 cents could make sense. If you are looking for coach tickets, I would find this harder to justify, unless you are flying routes that have sky-high airfares.So even in the best-case scenario, you’re still paying 2 cents per mile, far above the value most people reap from redemptions. That said, if you need either a very small number of miles or a very large number of miles to top up your account in a hurry (they take 72 hours to post), price out the option and see if it makes sense for you.DeltaIs currently offering a 75% bonus on purchased Skymiles until March 31, 2012. Delta sells miles at a pricey 3.5 cents a piece plus a 7.5% tax. With this promotion, you could get up 105,000 for $2,257, or 2.2 cents each. Not very impressive - especially since Delta recently let you buy miles for 1.1 cents each through their 100% transfer promotion. I would hold off unless you really need to top up your account.US AirwaysUS Airways is currently offering their Mastercard cardholders 50% off a mileage purchase thru February 29, 2012. US recently raised the price of Dividend Miles to match Delta’s sky high price of 3.5 cents plus 7.5% tax, so 50,000 miles cost $1,881 less 50% is $940.63, or 1.9 cents a mile. While not terrible, it isn’t as good as past sales that were as low as 1.5 cents a mile.This is probably the best deal out there right now, especially since US has a decent award chart and Dividend Miles can be used to book Star Alliance partner travel. [card card-name=‘Gold Delta SkyMiles® Credit Card from American Express’ card-id=‘22034414’ type=‘javascript’ bullet-id=‘1’]