He found DXF2GCODE (an open-source, genuinely free converter). It wasn't pretty, but it was trusted on CNC forums. He downloaded it from the official SourceForge page (avoiding fake "download now" ads).
The $300 Part and the Free Converter
A regular client, a local artist, brought in a complex, curvy design for a steel garden trellis. The artist provided a precise DXF file (a drawing from AutoCAD). Marco’s new (to him) second-hand CNC plasma table only read NC files (G-code). A software reseller quoted him $300 for a one-off conversion. Marco’s profit margin on the whole trellis was only $250. dxf to nc converter free