I agree, this is a nice thing you're doing for the less fortunate. May I suggest a slight alteration to the pricing? I'd sure hate to blow 5 mil and get nothing at all, so maybe 5 mil could be for the run and a credit for one free drop, which could be used during the run or carried over to subsequent runs (that 4 mil you mentioned).

A potential customer would be more willing to pay up if they didn't fear losing everything and gaining nothing. I know I would.