A simple way to take advantage of this would be to buy a $5 Amazon gift card, for example, and get 512 United miles; 10 miles for the purchase, 2 miles for the 25% cardholder bonus, and 500 first-time-bonus miles.
The Fine Print
- MPX purchase must be made by July 31, 2016
- Primary MileagePlus cardholders only
- Allow 6-8 weeks for bonus miles to be credited
This offer was reported on Reddit, and as far as I can tell from the fine print, this offer is not targeted and will hopefully work for any MileagePlus cardholder who never made a purchase using MPX.
Easy enough to buy a small gift card and trigger 500 United miles.
HT: gdq0 on Reddit