Before 2020, SketchUp sold . You paid a one-time fee (e.g., $695 for SketchUp Pro) and owned that version forever. You could install it on one machine, use it indefinitely, and receive maintenance updates for one year. After that year, you could still use the software – just without new features.
Many legacy Ruby scripts and extensions were perfected for the 2019 engine. Is there a "Free" Classic License? sketchup pro 2019 classic license free
If you are looking for a "free" version of SketchUp, you have two primary legitimate paths: Before 2020, SketchUp sold