For my 2 1/2D work, I use Draftsight cad (DraftSight - Free* CAD software for your DWG files - Dassault Systèmes) and Sheetcam (Welcome to SheetCam) combination. Draftsight is a free clone of autocad and can import dwg and dxf files as well as save them. It will not however do any conversion of pdf or image files, but you can import them and do tracing. Sheetcam is a reasonably priced cam program that will take various imports including dxf and has the ability to do leadin etc. Service is also great and improvements are being made all the time.
I find this to be a reasonably priced system for my uses, YMMV. Just a satisfied customer.
Art
AKA Country Bubba (Older Than Dirt)