This is a demo, so nobody can take it and nothing is paid. Take a real contract and you get a code and a link like these, made for you, so every download or sign-up you bring in is counted for you.
On Google Play, open your app, then Share and Copy link.
The page where people sign up. Each marketer's link to it carries their own tag, so your analytics can count the sign-ups they bring.
Marketers see every open contract and its price. Higher prices are taken first.
It turns into the marketer's own QR code and link, so the App Store counts their downloads for you.
How will you use it? You can switch later.