I don't find PSP at all comparable to Photoshop. As my for obtaining Photophop, my roommate got it through her school - Illustration major - and installed it for me.
I do know of people who've managed to download it and crackes to generate serial numbers as well, however, to get around paying so much. But the difference in pricing between Photoshop and PSP? Yeah you get what you supposedly pay for. Photoshop blows PSP way out of the water, in my opinion.