If cost is the primary barrier, consider (2D) or FreeCAD (3D). They are not identical to AutoCAD, but they can open .dwg files with reasonable fidelity.
For safe and legal use of AutoCAD 2018, Autodesk offers , educational licenses for students and teachers, and monthly or annual subscriptions . Companies should always use genuine software to ensure compliance, security, and full functionality.
The result? AutoCAD 2018 appears activated but never checks in with Autodesk’s servers.