Since advertising is on a Cost-Per-Mille (CPM) basis, for every 1000 impressions (impressions are calculated every time your advertisement is shown), you pay the specified CPM for that advertisement. For instance, if an advertisement is shown 5,000 times with a CPM of $2.00, the cost is $10 (5,000/1000 * $2).
How CPMs are determined
Since the platform is a closed ecosystem, only available to seller and buyers of a given show, your advertisements are shown to a highly curated and targeted audience. Unlike conventional CPM advertising, where your advertisement is shown to potentially millions of irrelevant users, advertising on the digital community touts quality over quantity of impression.