to create the things you create i want to teach myself how to make the cool sigs and stuff and maybe learn more things down the road

but iso the software

You could try GIMP. It's free and with proper plugins, it can be comparable to Photoshop.

http://www.gimp.org/downloads/

Be sure to look up some tutorials. I found GIMP to be a little confusing without a helping hand.

and with the right amount of time spent you can make some cool things with it?

Yep. It's relatively similar to Photoshop however since it's free, it is a little limited.
Generally speaking, it's your talent and skill that makes something - not the program and it's addons. Gimp works fine for basic things.

You could also try out a PS trial for 30 days (free).