EVERY FF program I have looked into has a program to sell miles to companies. Some publicize their programs more than others, and some have a large minimum quantity purchase, but I would be very surprised to learn that any major program would not do this.

I suggest looking at two factors:
- What programs are willing to sell you the quantity of miles you anticipate for the lowest cost per mile
- Which miles programs do your target audience value the most

I for one, would do far more to get 10K Asia Miles than 10K UA miles, etc....