Wow, this is a very detailed idea! This could have a lot of potential, but I see some problems. In my opinion, this is really going to be expensive to pull off. The startup is going to be very high, because you need a LOT of traffic for this to make it worth somebody`s money to be a provider. I wish I could help you calculate a # but it is beyond me. Running a regular ad banner on one of my websites versus one that has incentives are so different, I don`t think I could give you an educated calculation.
But I do have some things for you to think about:
The revenue sharing from the clicks to the provider is subject to abuse. It`s like the vote for the prettiest puppy contests. The mamas go to their favorite forum and says please vote for my dog, and then 500 of their closest friends go click as much as they can get away with. Your idea would/could be worse, because actual $$ are involved. So holding a carrot out for people to click doesn`t give much faith to the advertiser, because they are going to risk paying in vain. You`ll need a process in place to prevent that, but even if you had an IP blocker in place, there would still be the problem of everybody`s buddies helping them out, once each. You might even get a pact from the participants, to all click on each others ads `for the good of the community`. Some forums now are doing revenue sharing with adsense - they share with moderators or members, which is giving them incentive to click themselves, in hopes of making some money. That is instant disqualification from Google, but impossible to track if it is planned off site. It leads to a lot of abuse, and advertisers are paying 10 cents to 5 bucks a click for nothing.
Next - there isn`t a single advertising company that I know of that will put banners on your site for this purpose. Asking visitors to click is against all the rules of every company that I know of, because the advertiser wants people to click that are really interested. They don`t want a click and run on their tab. You will most likely have to generate this banner system yourself, which means you will need an accounting method, a validated system, a programmer, a lawyer and an accountant to sign off on everything, and you will assume liability for inaccuracies. You will also need to be insured in case you are sued by somebody who feels they are not paid correctly, or at the very least, pay for auditing, legal and accounting expenses for when these things do arise. These are probably not going to be brought forth by the little guy that puts up one item, or buys one ad, but instead from somebody that has paid a lot of money and feels they have lost a legitimate amount of money.
Lastly, I think you will have a hard time making enough money from the advertisers to make this profitable enough for provider to participate. If you look at your main traffic, you have freebie seekers. They are there because they want to win something for free, and that is the mindset they are in. They aren`t there to look for the best deal on an MP3 player from an electronic store, they are there to spend time clicking to win one for free. So getting them in the mood to spend money is something that may not happen, making the advertising more risky.
Also, ad revenue can be pretty cheap. Until you are really big, you might get pennies to a dollar per 1000 clicks. You`re going to need a lot more people than that to go around, because they may not click on every single giveaway, and it takes a while to build traffic. You can charge per conversion, but that would need further development in the banner system to know if the customer converted or not, and again, that might be low because people are there to win something for free, and not buy something. I help run a free support site, and we run in to the same thing with conversion rates. People are with us because it is free, and they`re not looking to buy the cow.
I wish I could help you more! Hopefully there is somebody here that may know more about liabilities and other legalities about running something like this. I think that is your biggest hurdle. If you can make it through that, my best suggestion would be to try and streamline the types of ads/giveaways. I said earlier to be careful so you don`t pigeonhole yourself as a comic book giveaway site, but that may be the smartest way to try this. If you appeal to a certain target group, it may be easier to get advertisers. I would be MUCH more inclined to advertise with you if I knew that you were a popular (or at least rising) site for kitchen gadget giveaways. That tells me that my target group will be foodies, or at least people that could be interested in buying some of my food. But if I`m going to be one of a kind, paired up with lawnmower salesmen and car detailers, then this may do nothing for me. All advertising is a risk, so do what you can to make it possible that they get a good conversion rate.
Hopefully somebody else comes along that knows just how to pull this off. :)