I am glad that Adobe is so expensive so when I started it was quoted at over a thousand local dollars while PSP was around $300 and I was guided to a comparable, superior in ways, product*. From a brief glimpse of GIMP I do not think it is a comparable product. I regret that the founder[s] of PSP JASC sold out since I do not think the 'service' I get from Corel is as good as that I got from JASC. My current problem of getting a DVD but no key to open it and several e-mails getting lost in their system kind of puts me off what is a very good product. But really there is so little 'improvement' possible with these programmes that it is questionable as if getting 'upgrades' is worth the effort.
*Over the years I have had a couple of versions of Photoshop and believe that if you start with one you are unlikely to meld with the other