Sometimes you not only need the correct tool for your job to make things done. Start developing with little applications without producing unnecessary costs is also essential to keep everything fine.
A really good solution is Firebase from Google wich is running in the architecture from Google Cloud. Firebase is more like a tool prepaired with a set of functions you could use.
For example you can handle your authentication in minutes with Firebase. But also to host your assets you are able to use the Hosting-Service by Firebase.
mobile and web
app teams succeed
This is what Firebase exactly do!
The best thing is, while you are starting with the application you are able to use the "Spark-Plan" for free. You don't have any costs from the beginning and if your project is growing up to something really big, just upgrade your plan or change directly to the Google Cloud console and update your architecture. Your project is already in the Google Cloud so it's really easy and no migration is typically required.