If you are just evaluating Saltcorn, you can use the free facility hosted on Saltcorn.com. If you use this facility, please be aware that there are no performance guarantees and that your application may be deleted at any time. Also, the way this application is hosted is less secure than self hosting, because each application is not well isolated from other applications.
If you want to use Saltcorn more seriously, we recommend self hosting. Saltcorn should in principle be installable on any modern Linux system. The main requirements are node.js v14 and a recent version of PostgreSQL. We have tested the installation on a 1GB virtual machine and this ran without any problems. One-click install is available from DigitalOcean
You can also run Saltcorn without PostgreSQL on Linux, macOS or Windows. In this case SQLite is used as the underlying database. This is not recommended for production, but you can use this to run Saltcorn on your desktop work environment to build your application and then backup the instance and restore it on a production environment.