Avianca LifeMiles is offering a bonus of up to 125% on purchased miles through December 20, 2016. You can buy up to 150,000 LifeMiles during the sale and get up to 187,500 bonus miles.

LifeMiles cost 3.3 cents each, so with a 125% bonus, you get the miles for 1.47 cents each.

Through Tuesday (December 6, 2016), you can buy IHG Rewards Club points with a 100% bonus.

Through November 16, 2016, you can buy IHG Rewards Club points with a 100% bonus.

Until Sunday (October 30, 2016,) you can buy Club Carlson points and get a 75% bonus on the points purchased. (I've been getting an error after signing in through that link. On the error page, add an "o" to the end of the URL, and it should take you to the correct page.)

Club Carlson points normally cost 0.7 cent each.

Until July 1, 2016, Starwoodis offering a 30% discount on the normal purchase price of SPG points.

Starpoints are normally sold in increments of 500 points for 3.5 cents per point. With 30% off, the price drops to 2.45 cents each.

The deal applies to all purchases of 5,000 points.

This is the second cheapest I’ve ever seen Starpoints sold, behind last month's 2.275 cents price that was only open to SPG credit card holders.

American Airlines is offering up to 100,000 bonus miles and 10% off on the purchase of miles through July 8, 2016. You can now buy 250,000 American Airlines miles including bonus for $4,311 or 1.72 cents each. That's the cheapest I've ever seen American Airlines miles for sale.

The discount is fixed, but the bonus miles are tiered, based on how many miles you purchase. The best deal is to buy 150,000.

American Airlines miles cost 2.95 cents each plus a 7.5% excise tax, and every purchase has a $30 processing fee.

Until today (June 3, 2016), Starwood Preferred Guest personal or business credit cardholders can buy up to 30,000 Starpoints with up to a 35% discount on the normal purchase price.

If you act today (June 2, 2016), you can get a 135% bonus on the purchase of Avianca LifeMiles.

You have to register for an extra 10% bonus on top of the automatic 125% bonus by entering your LifeMiles number here.

Through tomorrow (May 26, 2015), British Airways is offering a 40% bonus on the purchase of Avios. The biggest bonus ever offered on the purchase of Avios was 50% in February 2015, so this is a big bonus.

The maximum Avios you can purchase in a year is normally 35,000, but is being raised to 100,000 during this promotion. With a 40% bonus, that means you can add 140,000 Avios to your account.

Through Friday (May 27, 2016) at 11:59 CT, United is offering a 100% bonus on purchased miles. The size of the bonus depends on the number of miles you buy, with the largest 100% bonus kicking in at 40,000 miles purchased.

United miles normally cost 3.5 cents per mile plus a 7.5% tax, bringing the full price to 3.76 cents each.