I have done discounted promotions in the past, but we did revenue sharing and it turned out great. 100k free downloads is painful. I wonder if there is a way to

I have done discounted promotions in the past, but we did revenue sharing and it turned out great. 100k free downloads is painful. I wonder if there is a way to tell amazon to limit the free copies to the first 5k people who download, then go into discount mode.