US Airways is known for selling their miles at firesale prices and they just announced yet another 100% buy miles promotion until September 15, 2011.The great thing about this is that you don’t have to redeem those miles on US Airways - you can use them for flights on all 27 Star Alliance airlines: Adria Airways, Aegean Airlines, Air Canada, Air China, Air New Zealand, ANA, Asiana Airlines, Austrian Airlines, Blue1, BMI, Brussels Airlines, Continental Airlines, Croatia Airlines, EgyptAir, LOT Polish Airlines, Lufthansa, SAS, Singapore Airlines, South African Airways, Spanair, Swiss International Air Lines, TAM Airlines, TAP Portugal, Thai Airways International, Turkish Airlines and United Airlines.and other US Airways partners are: Bahamasair, Hawaiian Airlines, Virgin Atlantic, Jet, Qatar Airways and Royal Jordanian.The maximum amount of bonus miles per account is 50,000, so 100,000 miles will cost $1,478. 100,000 miles will get you from North America to Europe in business class roundtrip (60,000 for coach). 60,000 miles will get you to Europe in business class roundtrip, off-peak (Jan/Feb). 90,000 miles will get you from North America to North Asia (China, Hong Kong, Japan, Kazakhstan, Kyrgyzstan, Macau, Mongolia, S. Korea, Taiwan, Tajikistan, Turkmenistan, and Uzbekistan) and 110,000 is North America to Africa in business class (60,000 for coach).For full details of their award levels check out their award/upgrade charts on my master list page and read my post on maximizing US Airways awards. See also my last post when this deal ran in June.Overall, this is a great deal but do the math and check Star Alliance award availability (Continental.com, Aeroplan.com or using the ANA tool) for those flights you want before you buy. The bonus does post immediately, but you need to have had a Dividend Miles account for at least 12 days. If you don’t have a Dividend Miles account, you can open one here for free.I bought $1,478 worth of US Airways miles in June, so I’ll probably sit this one out, though I’ll probably help a bunch of clients and family/friends take advantage of it. As always, feel free to ask any questions in the comments section.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.Hat tip TPG reader Larry!T&COffer available for purchases made between August 8 and September 15, 2011, 11:59 MT. All purchases are non-refundable. Bonus mile amounts will be awarded upon completion of the transaction. The maximum number of Buy Bonus miles that can be received by one member for this offer is 50,000 bonus miles. All miles purchased beyond this limit will not be eligible for a bonus. Offer is subject to change. Offer cannot be combined with any other offer. Only purchases made online are eligible for the bonus. Miles purchased through Buy, Share or Gift Miles do not count towards Dividend Miles Preferred status. All other Dividend Miles Terms and Conditions apply. Please note that Dividend Miles accounts less than 12 days old are not permitted to Buy, Share or Gift miles. Award seats are capacity controlled and may not be available for the requested dates or mileage amounts.Miles are sold for $0.0275 per mile plus a tax recovery charge of 7.5%. GST/HST will be charged to Canadian residents. Miles purchased through Buy, Share or Gift Miles do not count towards Dividend Miles Preferred status. All other Dividend Miles Terms and Conditions apply. Please note that Dividend Miles accounts less than 12 days old are not permitted to Buy, Share or Gift Miles. All purchases are non-refundable.