A new free version is currently in the works for V5. I assume that once the V5 version is released to the plugin repo that will be it. The new version is currently in Beta https://www.advancedcustomfields.com/blog/acf-5-early-access/
At one time the developer said he wanted to release this new version to the WP Repo by the end of the year.
You might want to test it out.