Commission is paid per sale. Pixel or postback is fired from the checkout page once the conversion is logged from DCMnetwork. Further details in the tracking document.
Commission is paid per lead. Advertiser can mention terms on which leads qualify. Pixel or postback if fired on an action. For example, when a customer from DCMnetwork submits a form or clicks on more inquiry etc depending on the advertiser's site. Further details in the tracking document.