Its true about the mark up... We found a $500 Monster Cable at Fry's and just for Shits and gigles checked my discount on it and I could have walked out with that cable for under $300.
Hilarious! When I worked at best buy (communist blue box) just over 10yrs ago we got 50% off all cables and accessories. Huge mark-up because you know they were still making money even with the discount.