I'm not a lawyer, but my understanding is for Decker itself, yes. The MIT License basically means that Decker can be used for most any purposes, including commercially, with the requirement being that you put the license in the documentation.

It's worth noting that this applies to Decker itself and modules and such included in the example decks, but not necessarily other materials or resources - e.g. if someone else has made a contraption or a module and shared it then it may be worth checking with them how they feel about commercial use.

There are quite a few Decker projects that have "pay what you want" set on itch, and some have been included in Indiepocalypse bundles so there is some precedent for paid decks.

So I'd say that for Decker you're fine, but if you're using any resources from other community members and there's not an obvious license attached then you may want to check with them first if they're OK with it.

(Please correct me if I'm wrong about any of this)

Welcome to the Decker community!

Anything you create with Decker is yours.

Everyone is allowed to sell, exhibit, or distribute their decks however they like.

In addition to all the materials distributed with Decker itself, I extend this permission to any code or other resources I personally post in this forum.

It isn't a requirement, but I would appreciate it if people who make things with Decker included a link somewhere in or around their project to the Decker site and/or Itch page in order to help more people find out about Decker. We're still a very small community, and we need help to grow. Please also consider tagging creations with "#decker" so that your fellow deckbuilders can find your work!