Hey Jenn, Photoshop Elements is a good choice, especially if you've already had experience with the full version. GIMP is also very good, and FREE! They just did a huge update recently, so it's worth checking out. If you don't need any of the filters and photo-editing tools, and have used traditional media before, then Corel Painter is great. But it's a bit expensive, of course, unless you get it cheaper on Ebay or Amazon, which I did. As someone else mentioned, Manga Studio is very good, but if you don't need any vector drawing tools or the comic tools, it made not be right for you.
When ever you buy something make sure it has Photoshop.
I used ever version of Photoshop with demos and Limited Editions that came with other things like scanners, tablets, or computer software. The limited editions are the full versions, with a limited license, but even the full version only allows one user. So it is the same thing. Photoshop Elements does everything an artist needs, and there are a few things it don't do, but that don't effect an artist. I think Photoshop Elements is always under $100, but anything you can buy around $100 and get Photoshop Limited Edition is a real bargain.
I used the free (lite) version of Sketchbook and liked it well enough- but once I started working with Procreate on my iPad, I realized how limited it is. Too bad I realized that after I bought the full version. For $30- it is ok; had Copic colors, but not my favorite I guess. I just wish I could get Procreate to play well with other programs- but that's another thread all together.
hmmmm i see i think that it's all preference really and what you need im not crazy about autodesk sketch book i prefer using photoshop or just doing it by hand then using adobe illustrator to do vector inking. However, I'm really getting into doing 3d models and then taking them into photoshop or something and work off of that.