PDF & DXF to STEP Conversion

I am building a multi-part assemblie and I need step files for the various parts so I can do a higher level assembly, Some of the parts I am buying so they have PDF sheets, others I am designing pcb board... (Budget: $15 - $25 USD, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Printing, AutoCAD, CAD/CAM, Fusion 360, Mechanical Design, Solidworks)