Krusty said:MS Paint ... You *could* make skins with it, but it will take 1000x the effort and will look 1/1000th as good in the end.
This is most definitely the case. I made my 1st skin with MS paint, and it was a complete and total *****, and looked like crap. You have to do all anti-aliasing by hand and eyeball, 1 pixel at a time, without benefit of layers. I cannot advise against attempting this strongly enough. But I was happy enough with the result to want to do more skins, and thus could justify dropping the $$$ for a real editor.
But that's the rub: you don't know until you've made a skin whether you'll enjoy the process enough to justify the expense of a real editor. So my advice to you is either get a trial version of Photoshop or Paint Shop Pro, or try that free Gimp thing I've heard about but never used. Make a skin with one of these, and if you enjoy it enough to want to do another, you'll be cool with spending the money on a real editor.