If you decided to buy a license of TeamViewer, you will have a little shock because you reliazed that TeamViewer license is very expensive (for just a personal user) or even expensive for commercial user.
Believe me, i have tried a dozen times and it not worked so don't waste your time. But that's old tricks and didn't work anymore.
Most of them are relating to changing MAC address of your computer, uninstall and delete some folder created by TeamVIewer. There are some tutorials or tricks on the internet teach you how to bypass this Commercial use suppected.