This is a braindump of excellent tools & services that are free or really cheap that you can use to bootstrap something on the side.
I only include services with a generous enough free-tier plan that you can probably use it for a long time before needing to ugrade, reducing the pressure to make money from the beginning.
- Zoho: https://www.zoho.com/mail/ - offers a generious free tier that allows you to connect a single domain name, and a pretty decent user interface. They provide a catchall facility so you can receive emails on many different aliases.
- Mailerlite: https://www.mailerlite.com/ - their free plan gets you up to 1000 subscribers, and you can do automation on the free plan.
- Netlify: https://www.netlify.com/ - very fast static file hosting, which can grab whatever is in your Git repo and build it (from Github, Bitbucket and Gitlab), or you can configure a command line to upload your files from disk, or just drop in a zip file.
- Azure: https://azure.microsoft.com/en-us/ - offers some of their stuff on a free tier, for example some web hosting and function app usage. Might get you out of a sticky spot.
- AWS: https://aws.amazon.com/free/ - has both premium services free for 12 months and "always free" services.
- Firebase: https://firebase.google.com/ - BaaS - can use it to store data from a variety of clients e.g. a web browser, mobile app or backend app.