Thanks for your feedback. This definitely needs to be fixed/improved.
We are not pay-per-click or pay-per-impression network, these are just the rough estimates. The underlying principle is simple:
1. Advertiser creates an advertising campaign, selects targeting criteria, sets daily budget, deposits funds.
2. Our algorithm spends advertiser's funds on ad units (that fit targeting criteria) with respect to their weights (calculated based on unique impressions and other metrics).
3. Advertiser gets a share of impressions from each ad unit with respect to amount of money spent on it. E. g. if your campaign is responsible for X% of ad unit's earnings then you will get X% of that ad unit's traffic (no matter how much you pay in terms of BTC and how many impressions that ad unit generates).
This explanation is simplified, in reality there are many parameters that make the algorithm too complicated to discuss it here.
However the service is transparent, you can get pretty realistic expectations if you watch the network-wide stats (http://a-ads.com/stats) and stats of other active campaigns (http://a-ads.com/campaigns/). You can also see the stats of each ad unit and the share each advertiser has on it, e. g. https://a-ads.com/ad_units/1/campaigns
I'd advice to start an advertising campaign with small daily budget and gradually increase it if it goes fine. Just make sure you don't set unreasonably high daily budget if your targeting is narrow.
If you can track the performance of your campaign and make server-side HTTP call to reward efficient traffic sources, you might be interested in this offer: http://blog.anonymousads.com/2015/04/receive-free-traffic-pay-after-you-get.html
So did you looked into the issue so far? I would like to use it, but this issue keeps me hesitant.
I also think the captcha solution is not very elegant, i dont thing people will solve captchas just to watch an ad, it needs a more elegant solution to filter out clickbots
My solution instead the captcha would be: Dont count tor exit nodes or other public VPN's as clicks + tracking cookie + IP list of 24 hour visitors (and delete it after 48 hours to preserve some privacy of users).
It might hurt privacy, but there isnt any other way in accurate advertsing...
I hope i can give you good ideas to improve your service, a-ads is a really good concept