cable upgrades , real or rip off


im sure this has been done to death on other threads, but im somewhat new to the high end audio thing. but i must ask do these items make a huge diff. , a small one or something in between. i cant help but asking myself why when a company is trying to produce a knockout item such as a intgrated amp that costs say 3000.00 would they skimp on something like a 300.00 powercord if it would make there product sound that much better?
jrw40
Newbee, Bigtee and Nsgarch have given you good advice. IMO, the bottom line with cables is determining at what price point (for you and your system) you are better off spending the money on component or speaker upgrades vs. cables. You may also consider, DIY offers a relatively inexpensive avenue to compare different (but not necessarily better) cables, and also to learn a little about cable construction and the goals of cable design.
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Here's something I suggested to a friend (instead of pushing my own doga):

Try an assortment of inexpensive (whatever that means to you) powercords (or any other cable product).

Do you hear a difference? If so, explore moving upmarket...otherwise...
i thank you all for the advice, im still not sold but will probably end up trying it out if possible before buying.
thanks again
if you can, establish a relationship with a dealer who will agree to loan you cables for a weekend. put on those CDs/LPs you've listened to a million times and see if anything jumps out at you: are you hearing details you never heard before? is the bass better? is the overall tonal balance improved or just altered (some cables allegedly have a 'mid-bass bloat')? etc.

by the way, in the interest of full disclosure, I do think that going up from 'zip cord' cables can improve the sound.