When I talk about Node-Red, I almost always talk about running it on a Pi, but you don't need one! Learn how to install Node-Red on Windows, Mac, or Linux.
If you want a Pi, this is my favorite Kit: https://amzn.to/30VFKDF
My favorite Pi SD Card: https://amzn.to/2JXqyjz
The Orange Pi is a great Node-Red device: https://amzn.to/30Y7kQt