Lifemiles has brought back the 2×1 promotion for buying Lifemiles. You have the option to buy Star Alliance miles at 1.5 cents/mile.
My advice on the course of actions hasn't changed since October when they ran their last share miles promotion.
While it may be a good idea to just purchase miles speculatively it's better to do that with a specific flight in mind. Avianca keeps running these promotions at least once a quarter though you can't be sure there will be a next time.
Log in to your account and search the flights you have in mind and see if there is going to be availability. Avianca is unique that it almost exclusively trusts the computer with possible routes. You can't just make up routes and call without fluent Spanish and tons of patience. The online booking system works well but comes up with odd routes sometimes and only works in one class (i.e. for all the legs between origin and destination the desired class of service must be available or the booking system won't show it.).
Terms and Conditions
This promotion is available through Avianca Call Centers, LifeMiles.com and Avianca Information Centers, except Colombia where is available only through the Call Center and LifeMiles.com.
For residents of Venezuela, it is only available through LifeMiles.com.
This promotion is available between December 3rd, and December 30th, 2013, as the last date of purchase.
Minimum of miles to buy per transaction: LM 1,000. Maximum miles to buy per transaction: LM 75,000.
Maximum miles to buy during a calendar year: LM 150,000 ( the purchase of mile bonus accounts as an annual purchase). Miles must be purchased in multiples of 1,000. Maximum number of transactions: 1 transaction.
At LifeMiles.com, the purchase can only be done through Earn/Buy LifeMiles.
Does not apply to the Flexible Redemption (miles + money) during the payment process of air ticket redemption. Each package of 1,000 miles costs USD 35,40, including all taxes applicable to each country*.
The cost per block of 1,000 miles may vary according to the country or channel of purchase. Form of payment through Call Center and LifeMiles.com: International credit or debit card. Cash payments are only allowed at Avianca Information Centers. Other conditions: Applies only to members enrolled in the program prior to December 3rd, 2013. The miles purchase transaction receipt will show the total of miles credited to the customer's account, including bonus, and the total amount charged for the transaction. The miles bought and earned with this promotion do not apply to achieve Elite status.
The amount paid for the miles purchase is not refundable. The miles are not endorsable. Miles purchased, once accrued, can be redeemed in accordance with the conditions specified in the LifeMiles Program Terms and Conditions and the portfolio of products and services available for redemption. LifeMiles Terms and Conditions apply. *The price may be lower depending on the country of residence registered in the members account in the database.