I bought over a million Kellogg's AA miles via cereal and Eggo waffles (prior to the miles limits imposed in later years). The Sam's Club manager was willing to order an extra pallet of waffles for me.

Called food banks and rescue mission ahead of time, let them know that I was bringing frozen waffles and would need some assistance in cutting off the certs. There was no shortage of labor available - after breakfast, several homeless men and volunteers were very happy to help remove the certs. Best part, just like Pudding Guy, I took income tax deductions for the donated food, reducing the net cost of the miles to about two-thirds of a cent each. Not as cheap as Pudding Guy, but cheaper than most mileage runs.