Hi.
No you don't NEED a VPS. But if you have any chance of virus, malware, spyware or keyloggers on your decent PC and laptop then that might get you hacked. Also, it's nice to have a 24 hour a day, 7 day a week uptime. Backups of your machine while it's running is easy on a VPS. And you can click to upgrade your CPUs or RAM with a VPS easier than you can upgrade your own physical machine.
But you don't need a VPS.
And buying a license from a user on here will get you the license key. Just make sure its a legitimate license key that is verified by Gunthar.
Resellers can help with set-up, help purchase a VPS, help with recommending which version of the bot you run, etc, etc.
(I'm not a reseller).