EDIT: Mip, I would not call AutoDesk Inventor a low cost solution. I think it fits in the "big ouch" cost solution category.
I work for a game company Mip. My idea of big money is slapping a texture and material, resembling gold, on a 20 foot long rectangular primitive scaled to fit on your screen.
I've been doing CNC work since I was 18 (Now 47) (holy crap that 29 years) and have been in business for myself for 13 years now doing Wire EDM work. I've used just about every CAD package on the Planet.SolidWorks is hands down the most powerful and intuitive. AutoCad (Autodesk) is the mainstream and probably the hardest to learn (as many of you already said). But for what your trying to do there are many low end packages out there that would do the job. Under 1K is gonna be tough to find though. I'd have to agree with the others, get someone to do the design work for you. I think the estimate of 300-400 and hour is a bit high for Cad work, at least in my area. Also DFX is a 2d file exchange. Use IGES for 3d translations, many today also support Step Files which will work fine. Just my 2 cents.
Savage, I just noticed your from Murfreesboro. Many moons ago (Late 80's) I worked for McMinnville Tool and Die and lived on 70S just west of the small airport there. Probably about 30 minutes from you.