If you only need to open, review, measure, or present Revit files (.RVT) without actually modifying the 3D geometry, you do not need to buy a license. Autodesk provides free viewing tools. Autodesk Viewer
Blender is a famous open-source 3D tool. With the add-on, you can open IFC files (the open standard for BIM). You can export from Revit to IFC, then edit it for free in Blender. It is not Revit’s interface, but it is incredibly powerful. free autodesk revit
If a website promises you a "lifetime license for free," it is either a virus, a demo from 2012, or a scam. If you only need to open, review, measure,