+1 on the ~10% general guideline
Lots of variables in the equation and there appears to be no ceiling in the upper end cost
Though there are are some price performer gems, while not the best sounding cable, that still sound great and provide better ROI
Just to name a few in my limited travels
Audio Envy
Morrow
Silversmith Fideliums
Users of Blue Jean cables consistently provide high customer sat ratings as well
Enjoy the journey