Through September 25, 2017 you can buy Flying Blue miles with a 100% bonus. That brings the standard price of 3.28 cents a mile down to 1.64 cents a mile.

The minimum amount of miles you have to buy to earn the 100% bonus is 4,000 (for paying roughly $131.50 you'll receive a total of 8,000 miles).

Until today (December 31, 2016), you can buy up to 30,000 Starpoints with up to a 50% discount on the normal purchase price.

The discounts are targeted. To see your discount, sign into your SPG account at this link. I was offered the maximum, 50%, discount on purchases of 5,000 or more Starpoints, and I bought 20,000.

Starpoints are normally sold in increments of 500 points for 3.5 cents per point. Getting a 50% discount brings the price down to 1.75 cents per Starpoint.

Until today (December 31, 2016), you can buy Alaska Airlines miles with up to a 40% bonus. Log in to your account at this link to see your offer.

The sale is structured as a bonus on the normal number of miles you’d receive.

The bonus is tiered, so the biggest 40% bonus comes from purchasing 40,000 to 60,000 miles at the normal price of about 2.96 cents each after tax.

It costs $1,774 to buy 84,000 miles (60k + 24k bonus) during this sale.

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.