American Airlines has had monthly promotions for buying miles. Thing to remember is that you can only buy or be gifted maximum of 40K American Airlines AAdvantage miles on a calendar year. You can access this offer here.
The current offer is for maximum of 12K bonus miles for buying 36K to 40K AAdvantage miles. If you buy the minimum required to get the maximum bonus, the price of a mile under this offer is 2.3 cents each.
Last month the maximum number of bonus miles was capped at 10K and the price of a mile was 2.4 cents.
This is not the best offer for buying American Airlines AAdvatage miles that have been out there lately. If you do, however, need a small number of miles to make that international business/first class trip to happen, it can make sense.
Here are the terms and conditions of this offer:
Transactions are nonrefundable and nonreversible. Please allow 72 hours for purchased AAdvantage® miles to post to the designated AAdvantage account. Please allow 5 days for the bonus miles to post. Members must purchase 6,000 miles or more in a single transaction from the buyAAmiles® program beginning 12:01 am CST November 1, 2012, until 11:59 pm CST November 15, 2012, to be eligible for the bonus mile offer. Members will earn 2,000 bonus miles for every 6,000 miles purchased in a single transaction, up to 20,000 bonus miles. The bonus is awarded to the purchaser of the miles. buyAAmiles transactions are limited to a combined maximum of 40,000 miles per account, per calendar year. Bonus miles earned do not count toward the annual limit. AAdvantage miles purchased or earned through this promotion do not count toward elite-status qualification or Million Miler(SM) status.