Speaking as someone who perpetually nurses a repetitive stress injury similar but more intense than carpal tunnel... you might want to look into a different style desk and chair that will reduce chance of injury.
I have a very not-impressive, cheap setup. I spend no more than 6 hours at this desk at any given time, so maybe I'm not the best to offer advice. Still, I'll throw it out there to show you a working, injury-free setup can be cheap.
My textbook is wedged under my laptop to keep air moving, and to hold my place. I have a low pull-out shelf for my keyboard and mouse, situated in such a way that there is no strain on my wrists. I use a notebook as a mouse pad because it is raised more than a typical mouse pad, which works better for my wrists. My screen is a solid two and a half feet away from my face to encourage me to look around my room periodically to prevent eyestrain.