For a while now I've been building new projects on a framework that I've dubbed the "Free Startup". It's a technical framework that allows you to build an MVP as quickly as possible, with 0$ in technical investment. The only thing you need to bring is your time.
Development Environment - Whatever you want
Pick whatever you want! I'm a hardcore vim user, but you're probably not what my team-mates call "a dinosaur". Netbeans, IntelliJ, Atom, Notepad++, Emacs. Whatever you want - chances are your dev environment is available for free. Even some of the last holdouts (Visual Studio) offer free versions (and there's also VSCode). Pretty much everything is available for free.
Code hosting - GitLab
There was a time when I would suggest GitHub as the end-all to all your code hosting scenarios. It was free for public repos and seems to be the defacto location for most projects. It's honestly a good platform, but I find I prefer GitLab way more. It's free, gives you private repositories, and essentially replicates the feature set of the current incumbent, GitHub. The nice thing about GitLab is that it gives you pretty much all the GitHub features, for free, and also includes projects, fancy issue boards, and so much more.
GitLab is trying to combat GitHub's current hold on the developer market by building everything you need under one roof. That means it's also got a really sweet CI/CD experience. Very similar to CircleCI. It's a yaml based configuration that allows you to build your project in containers. From there you can hook it directly into Heroku so that merges to different branches automatically deploy!
Communication - Discord
Inter-project communication is really vital for the existence of your project. Slack is the defacto for a lot of people here - however, as a developer that works with other people, Discord is something I've found myself drawn to more and more. It's very easy to get started with, and gives you a great mechanism for on-demand voice chats. It also has a simple webhook system that lets you hook in GitLab + Heroku events so that you can get CI/CD updates right in your chat interface.