United currently has a social media promotion on Twitter:
Save up to 30% when you buy your miles HERE
You can purchase MileagePlus miles for yourself directly from HERE
Or you can purchase them to give to others directly from HERE
There’s a minimum purchase of 5,000 miles, up to a maximum of 150,000 miles.
You may need to hurry, though. This promotion ends 11:59 p.m. CT (Chicago local time) on July 11, 2014!
Terms and Conditions
To take advantage of this offer, you must use the order links shown above. Minimum purchase of 5,000 miles required for this promotional pricing. Buy 5,000 to 14,000 miles and receive a 20% discount, or buy 15,000 miles or more for a 30% discount. Miles are available in increments of 1,000 up to a maximum of 100,000 miles, and in increments of 5,000 up to a maximum of 150,000 miles. Purchase up to 150,000 miles per account per calendar year.
Displayed price includes all discounts and taxes. Credit card will be billed immediately upon purchase. Mileage rates and other fees and offer terms are subject to change. Allow 48 hours for miles to process and post to your MileagePlus account. Miles are nonrefundable. Promotional offer valid until 11:59 p.m. CT (Chicago local time) on July 11, 2014. Purchased miles do not count toward MileagePlus Premier® status. All MileagePlus Program Rules and terms and conditions apply.