AviancaTaca is offering a 100% bonus on the purchase of Lifemiles through August 31, 2013. Through this promotion you can purchase a maximum of 75,000 Lifemiles (plus the 100% bonus), for a total cost of 1.5 cents per mile. The promotion is also only valid for those that were members of the Lifemiles program prior to August 1, 2013.
There are some major pros and cons to the Lifemiles program. Some of the major pros are that they allow one way awards, don’t impose fuel surcharges, and have an attractive Star Alliance award chart. Also, as long as you have 40% of the miles needed for an award ticket, you can purchase the remaining miles at the time you purchase your ticket. The remaining miles used to be offered at 1.275 cents each if you purchased 60% at the time of ticketing, though now the cost is a ~1.56 cents per mile, so it’s not as good of a value anymore.
The single biggest con, which is simply ridiculous, is that they don’t let you mix cabins on an award ticket. That means if you book a first class award all segments have to be in first class, which sucks, since lots of flights don’t offer a first class cabin. This greatly limits the potential of these miles, in my opinion, since I can’t remember the last time I redeemed miles with all travel in a single cabin.
So this isn’t something I’d speculatively take advantage of, but if you have a specific use in mind — in particular Lufthansa first class — this can be a great value.