Illustrator is not crap at all, it's just a very specific tool. It's the best thing out there for vector art, and it's way better for text layout and graphic design than Photoshop (though not as good as InDesign, obvs, but there's a very steep learning curve there).
However, if you're not doing vector based art or simple graphic design (and you're probably not) you really have no reason to use it. If you're trying to make pixel art, specifically, you really have no reason to use it. It just doesn't do that.
As to the question at hand: I would say if you don't understand the difference between Photoshop and Illustrator, you probably shouldn't be buying either.
I would start out by trying out gimp, or pretty much any other free graphics editing software.