Reducing mesh in editor-possible thru code?

I have a need to create reduced mesh polys within a scene. There are way too many options in the asset store, with assets costing from 5 to over $200. I don’t need automatic LOD creation since I can use the LOD group feature of Unity Pro.

So as an option I was wondering if it is possible to do dynamically thru code. Take an existing mesh and reduce the poly count dynamically at runtime

Yes, it’s possible. That’s what the assets on the store are doing; it’s not really relevant whether it’s done in the editor or at runtime, since the actual mesh reduction code would be the same either way. The LOD group feature of Unity (not Unity Pro; Unity personal and pro have all the same features) doesn’t generate reduced meshes; it’s up to you to supply them. Essentially what it does is calculate which mesh should be displayed.