Hi @LightBen welcome to the community. I moved this question to the cms platform section.
There are different ways to have multiple users using Netlify CMS. Some are free and some paid depending on your needs.
Netlify CMS is open source, so it is free to use and host on Netlify. There are multiple ways to use the cms with GitHub that allow for multiple users.
git-gateway as the backend which requires using Netlify identitiy, which allows some free invite only users (5 as of this writing) under the free plan per site. The next tier requires a level 1 plan. Prices can be found here. Netlify Identity allows users to login without having a git provider account.
When using github, gitlab or bitbucket as the backend, anyone with access to the git repository can log into the cms and make changes when hosted on Netlify.
There is the ability to host the cms on your own, but that would require you setup your own oAuth authentication on your hosting server. This option is substantially more complicated.
- Roles are not supported for users yet (track here)
You can ask about other requirements and setups in the cms community chat (gitter) here