Remember when they made games? They ruined counterstrike

Maybe i'm a brainlet but the developer sets the price on the steam marketplace, all valve asks is for you to keep the prices equal between market places, and when a sale is offered make sure to offer a comparable sale to steam users as well.

Also the article details that the steam developer agreement is private, but you can infact find it on Valve's own website (https://partner.steamgames.com/doc/gettingstarted) Which details everything that you must have and rules you must follow to become a distributor on the steam marketplace.

This could open a Pandora's box.