In keeping with today's theme of buying Loyalty Program miles or points, US Airways is currently running a promotion that actually is a great value. Basically they are offering to double the number of miles you buy from them, up to 50,000 miles.

So if you buy 50,000 miles at 2.5 cents per mile for a total of $1250 plus a $30 transaction fee, you will get another 50,000 miles for no cost. US airways is not the most lavish of airlines out there, but you can also redeem these miles for flights on other Star Alliance Airlines, making these miles a great value.

100,000 miles are enough to travel from North America to South America in First Class, or 80,000 miles ($1000) will get you from North America to Europe in Business Class on a premium airline like Swiss or Lufthansa.

But it doesn't stop there... You can also gift or share miles with another Mileage Plus member, and he will also receive a 50% bonus for free. So although the maximum bonus you can receive with just a purchase is 50,000 miles, when you include the other two options, you can actually receive 150,000 miles for free. Combined with the 50,000 you buy ($1250), and the 50,000 that someone else buys and shares with you ($1250 + $500), and the 50,000 someone gifts to you ($1250), you can end up with 300,000 miles for $4250 (plus $90 in transaction fees) and that is enough for two tickets from North America to Africa in First Class, or a single Around the World ticket in Business Class.

Both great deals!

This offer is valid through the end of 2009, and bonus miles apparently will be awarded as soon as the transaction is completed!

• Darren Mak's blog