Well, i don't know how things are now, but about the time that Mercedes came out I made a small penny selling stat % all class armors i fused together using black smithing. I was selling them about 1-2m meso each if they were 2%, i think 4-5m if they were 4% stat.
This was in El Nido economy though, before it got merged.
It's slow going though, even with a shop permit.
Make life what you want it to be.