Dude, don't listen to him.
Wow.
Mr_P3rf3ct, you're hardly the authority on industry art practices, so please don't try and sound like it. It's pretty rude to knock someone's information aside like that, especially given their comparable experience to your own.
I'll grant you that, much like 3d modeling packages, you can learn and practice the underlying principles (of art, of box/organic modeling, and so on) in freeware or in multi-thousand-dollar software with little difference. That part of the message is fine. So for someone still getting their feet wet in producing artwork, use whatever is available. Just know that if you do pursue the career into more professional settings, it'll benefit you greatly to learn Photoshop's workflow and interface, some of the tools available in the PS suite are incredibly handy, and as multiple people have pointed out, it interfaces better with many standard tools much better than any other option.
This is coming from someone that works primarily in Blender and Sketchbook Pro: I would give an arm for some of Photoshop's tweaking tools alone, they blow Sketchbook's manipulate tools out of the water; and ZBrush is on my wish list for its UV and texturing pipeline, even though Blender has its own sculpting suite. The bottom line is about efficiency and speed. Often the difference between pro(industry) artists and hobbyists/amateurs isn't the quality of work (there are a LOT of great artists out there) but how fast they're producing art at that quality.