I don't really blame retailers for their huge markups on cables. See: http://consumerist.com/353938/monste...off-80-markups
After all, consumer electronics is fiercely competitive business and margins are slim. They have to make money somehow. They do it, in part, by selling overpriced cables, other accessories and stuff like extended warranties (another big rip-off). I guess this helps keep prices down on the stuff I buy, so I should not complain.
But I do object to salespeople who mislead by saying things like "you should "invest" in the "best" cables you can afford to get the most out of your system, the picture will look much better, these cables will last longer, etc." So far, I have never heard of any HDMI cables "wearing out"!