United has announced a 25% discount on roundtrip economy class awards between the United States and Europe. That means your trip to Europe would cost 45,000 miles roundtrip instead of the normal 60,000.

Details:

Only valid when booked by June 28, 2016
For flights flown:

between the United States + Canada (not Hawaii) and Europe
between August 23, 2016 and March 31, 2017
on United planes only

Blackout dates on which you cannot book with the discounted price: December 15, 2016, to January 8, 2017
Roundtrip only, one ways will maintain the normal price of 30,000 United

My friend, Sarah Page, recently took a trip to Brazil to escape the dismal winter weather in Buenos Aires that drove me to Brazil and then Europe myself. She and her friends used tips they learned from this blog to save money and earn extra travel rewards on the trip.

I will go through those tips below so you can learn from their experience. (Ignore the fact that she started in Buenos Aires.

Travel from San Francisco, Washington DC, Cleveland, Houston, Denver, and New York to Zurich, Switzerland; or Frankfurt, Germany for $414+ in American Airlines economy. Most of the availability for these deals is between September 2016 and April 2017.

The Citi® / AAdvantage® Executive World Elite™ MasterCard® 60,000 mile offer has expired.

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.

The Alaska Airlines card from Bank of America now offers 30,000 bonus Alaska miles after you spend $1,000 on purchases in your first 90 days from account opening.

The previous public offer had been 25,000 miles for a long time with frequent 30,000 mile offers and an occasional 40,000 mile offer, but Alaska Airlines announced its plan to go to a 30,000 mile bonus this spring in a February stock market filing.
Quick Facts

Sign Up Bonus: 30,000 Alaska miles after $1,000 in spending in the first 90 days
Category Bonuses: 3

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.

Update 5/25/16: A One Mile at a Time commenter confirms booking a Brussels Business Class roundtrip from New York to Brussels for 36,620 Etihad miles plus under $100 in taxes per person.

American Airlines is offering up to 15,000 bonus miles and 35% off on the purchase of miles through June 1, 2016. You can now buy 165,000 American Airlines miles including bonus for $3,122 or 1.89 cents each.

The discount is fixed, but the bonus miles are tiered, based on how many miles you purchase.

Delta domestic economy and Delta Comfort+ award tickets are on sale for as little as 5,500 miles one way.

Book by June 7, 2016
Travel August 23 - November 16, 2016 (except September 1 - 8)
Fly one of 8,000 routes on sale (although only a few dozen are listed)

I searched for Columbus to Los Angeles and found the sale price widely available in economy and Comfort+;