It's true. Power cords are expensive and seem less influential
than most other cord types. However, an Acoustic Zen El Nino should be about a hundred dollars used and it probably will make a very slight improvement in the sound of your system. Also, as long as it is good condition, a used cord is always a better option. They don't need break in and will always be cheaper. New power cords, and I have spent thousands on them, just don't justify their cost. Have you tried a power conditioner? There are some on the market that would prove a more cost effective power grade than a power cable and they can serve to improve the performance of other components in your system as well.