United is offering a quick 3 day sale that provides you with 50% more miles when you buy award miles for your account.

The sale is set to end at midnight on July 30, 2015.

To take advantage of the offer, click here to be taken to the Mileage Plus log-in screen.

You can buy up to 100,000 miles from this promo (you’ll receive 150,000 total miles).

These opportunities are usually worthwhile if you need to top off your accounts in order to redeem for Business or First Class travel on Lufthansa or another LH Group airline.