Thanks for your question and welcome to the Prodigy community
You can install on an unlimited number of machines!
Prodigy's license applies to people (developers), not machines. For example, if you have a personal license, that provides you (the person listed on the license) to install Prodigy on an unlimited number of machines with an unlimited number of annotators. What you can't do is provide someone else access to your code base since you are the only one listed on the license.