It looks like the flash sale that United had for buying miles back in May may have been a good test at what are ideal bonus rates for buying MileagePlus miles as now we see the exact same offer come out for most of the summer! When buying at the 100% level you are essentially getting the miles for about 1.88 cents each.
Up to 100% Bonus MileagePlus Miles when you buy or gift miles online. Full details Until Aug 15, 16
Buy 5,000 – 19,000 miles | Get a 25% bonus
Buy 20,000 – 29,000 miles | Get a 50% bonus
Buy 30,000 – 75,000 miles | Get a 100% bonus
Can’t make use of this offer? Find many more United MileagePlus bonus offers here!