US Airways has a new 100% bonus for buying or gifting Dividend Miles by (expiry unclear but likely end of February), 2014. This offer is available for US Airways credit card holders.
You can access US Airways web page for buying miles here, where you can check your eligibility for this offer.
The price of a mile under this 100% bonus offer is 1.88 cents each.
Does it make sense to buy Dividend Miles at 1.88 cents each?
US Airways has number of promotions yearly for buying, gifting, and transferring in points from hotel programs to Dividend Miles.
This 1.88 cents per mile offer has been one of the lowest purchase offers. There have been offers for gifting miles that allow you to “purchase” miles at 1.1 cents each.
Conclusion
If you have firm plans to use these miles and the availability exists on Star Alliance carriers, I would go ahead and buy.
The airline exits Star Alliance on March 30th and enters Oneworld as an affiliate on March 31, 2014. These mile will eventually turn to AAdvantage ones once the programs are merged.