I'd recommend Elements if you can get only one.
I tend to use it in conjunction with Serif Photoplus X2, which does some CS3 like things in 8bit that Elements can't. I think it cost me $60 or thereabouts. Photoplus has imho a brilliant mono converter; some of the rest of it can be a bit clunky; it does masks, filter layers, loads more adjustment layers than Elements. Text handling is in another league. Most Photoshop 8bit plugins will work in Photoplus, but it can be twitchy about them.
I have both progs running now when editing - using copy and paste between them to do bits in each of them as necessary, but they have strengths and weaknesses - sad isn't it?
I have used Gimp, and it is definitely very powerful - and as it is free you have absolutely nothing to lose, but a lifetime of being in hock to Adobe, if you find it is the one for you. Gimp has its own set of plugins, Photoshop ones will not work.
You might also want to look at PaintShop Pro X2 from Corel. I'm not a user, but it has a loyal following. I didn't go for it because at the time it did not support my Fuji RAFs.
Elements also has Adobe's rather good camera raw built in.
Whatever you chose, have fun learning.
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