That's an interesting concept, though I'm not so sure that this type of program exists just yet. Mind you, I haven't been able to try many of the ad companies on the Internet, so it could be out there.
One program you might want to look into is Amazon Affiliates (they have different branches for US, UK, Canada... etc. I've made an account with a few of them.) I know that one of their payment options allows you to order things from their site. So, once you've sold enough of their products on your website to have earned at least $10 (they give you a small commission from each sale that you refer to them), then they can give you sort of like an e-giftcard, which you can use to order things from the Amazon website.
I'm not sure if this is available to all countries, or exactly how it all works, because I've only accepted checks from them in the past, but it might be something worth looking into a little deeper. Obviously it's harder to have someone click a link and then make a purchase, than it would be to have them simply click on an ad like with Adsense, but it might make a little money if you can't find anything better.
I've used Amazon on my websites, with limited success. Though my Adsense outdoes it each month.
Anyway, best of luck on your search! If you find something, be sure to let us know

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