Why Android Studio is free and PhpStorm is not?

Question

Wondering why the same company sells only some of its software

Answer 1

it is because of the license
Android Studio has Apache License and PhpStorm has Proprietary
Every Software​ has license. Some are free to use some are not(commercial).

Simply even they are coming from some company they have different license.

Answer 2

Android studio is based on " intelliJ community edition" which is a free software.
Also, as Eranga said softwares can have different licenses