As title says, I need help regarding this.

I am nearing level 50 and to the end of the main campaign, and I have been reading here and there about the relic weapon, but I am not sure what is needed exactly.

I have seen Erudite's Picatrix of healing in the marketplace, regular quality and the high quality one.

Does it make a difference if I purchase a high quality one with the melded materia onto them?

Worth investing about 140k for one of them?

What exactly is needed besides starting the questline for it?