[freedumb2003]

Jewelers are the worst:

ALL DIAMOND JEWELRY 80% OFF! (of the price marked up 200%)

[fanfan]

The problem is that when a retailer offers a product for a reasonable or fair price, people don't think they are getting “a deal”.

Everyone wants a “deal”.
I sell a product for $700, and put it on sale for $600 occasionally, and people still ask for a discount.
Someone else sells the product for $1100, and puts it on sale for $800.
They offer a discount of 15% off "their regular price" to almost anyone. People pay almost $300 more than they need to, and they actually think they “got a deal”.

That human tendency explains this tactic.