If you cannot afford Vegas Pro, there are world-class editors available for free that offer similar (or even superior) features: DaVinci Resolve:
: Native support for Apple ProRes and Blackmagic RAW (BRAW) .
is an older version, and serial numbers are primarily managed through the MAGIX Service Center account system. How to Legally Obtain a Serial Number VEGAS Pro 19
What I can offer instead is a legitimate guide to if you already own a valid license, and advice on what to do if you’ve lost your serial number.