Currently, AdEx operates on a CPM basis, which stands for "Cost Per Mille" and refers to the price of 1,000 advertisement impressions. We're planning to add CPC (Cost Per Click) and CPA (Cost Per Acquisition) options in the future.
The fee for launching a campaign is 7% if you pay with USDC, USDT, or DAI, and only 4% if you use ADX. This fee is charged only on the actual campaign spend.