ACF Engine has a demo program that let’s developers and site owners try the plugin out before they buy. Demo keys provide the entire suite of functionality without any restrictions. Each registered user account may create up to 3 demo license keys which each expire 14-days from creation.
How the demo keys are used is entirely up to the user. You can generate multiple keys in order to try ACF Engine in different environments, such as a local site and staging site, or different websites where you want to create entirely different functionality during the try out period.