You don’t always need an Advanced key. The standard version of iLO 4, which is free and built into all ProLiant servers, already includes: HPE iLO standard and licensed features
The most reliable and legal way to get a free iLO 4 Advanced license is through HPE's evaluation program: hp ilo 4 advanced license key free
While is built-in and free, it has major limitations that make the Advanced license highly desirable: You don’t always need an Advanced key