Yeah Retopoflow is paid and also still in the Beta stages, but I wanted to support the devs. Just saved up for it.
That was the one from the video that he mentioned: decimate will probably do well enough for you. Save a copy of your project before you do it though.
There is also a BlenderGuru video that I thought went pretty well into basic uv unwrapping quick and dirty for those who aren’t great at retopology and just want to get into the shading/texturing portion of their model.
I’ll post that link here as well because I like his stuff too:
https://m.youtube.com/watch?v=Ebx2qbBlvh0