Actually, why not check out https://gamedev.market/ for some 2D and 3D art.

I've been interested in character design and modeling people There are some programs out there that let you create something without the artistic skill, but you're probably always going to just be selecting from pre-sets that someone else created.

I'm afraid that truly unique character creation involves a tremendous amount of work and learning. I'm not sure there are any short cuts that won't just result in choosing from pre-created options that someone else designed. As I explore this topic it seems to me that if you want to be good at it and create truly unique characters, you have to do it the old fashioned way and learn artistic anatomy and traditional design.

Still, there are programs out there like Make Human that allow you to create something from a given set of options. Costume design and what-not is still something else entirely. Again, not sure there are any short cuts.

If you're really strapped for time or just looking for a way to at least get started with character design, you could use Photoshop (assuming your school has it or you can afford it) to make a character using simple shapes. It doesn't even have to look exactly human at first, but at least you'll have a silhouette to work from. From there, you could keep sculpting (for lack of a better term) until you have something that looks decent enough.

All you'd need are just the simplest tools (Rotate, Shape Tools, Line Tool, etc) You'd have to play around with multiple layers for each body part and also for shading/coloring, but it wouldn't take too long to learn how to use layers. You could also use Pixlr Editor for free if your place doesn't have it. Sonny and Sonny 2 have sprites which are more-or-less the product of a simple process like this.