Get a student copy of AutoDesk. As someone who works in the blueprinting industry, you'll find more support for that program and its exportables than the others. It's a bit more expensive than some of the others, but I think you can get a student version for $300 or so.
It will add a stamp onto your plots that says, "PRODUCED WITH A STUDENT VERSION OF AUTODESK". You can get around this by plotting to a larger canvas size than is needed, then cropping the image... (you'd think they'd figure that one out).
Also, DXF's are a very common format for CNC Mills, so if you plan on having something doing the cutting for you on a material, AutoDesk has it ready to go without having to convert the files or buy add-ons and drivers.