UPDATED 2020: How to reset JetBrains WebStorm evaluation period in Windows

First of all - it's illegal. Do it at your own risk!

• Delete \Users\user\.WebStorm*\config\eval folder
• From file \Users\user\.WebStorm*\config\options\options.xml remove lines contains '*property name="evlsprt*'
• In Windows Registry remove all keys inside HKEY_CURRENT_USER\Software\JavaSoft\Prefs\jetbrains\webstorm

That should be it. But buy it if you like it!

P.S. Since version 2018.3  you can find evlsprt in the file
\Users\user\.WebStorm*\config\options\other.xml

UPD:

Since version 2020 you can find settings and eval folder here:

\Users\%user%\AppData\Roaming\JetBrains\WebStorm2020.*\