There aren't any features locked behind a paywall, and they will need it to cost some amount of money on Steam until they have a reliable amount of skin designers. I think if they made a community tab where you could post your own skin ideas/designs, and posting on the community tab makes you sign an agreement where you can't sue among us (because you CHOSE to give them your design to support them), then they could make the game free and make people pay for skins. I guess it would be cool too if the person who made the skin gets it for free, and if you could only post a skin once every 14 days...