Good commerce isn't trickery. It's what separates a real business from a mere enterprise. I've written and deployed collaborative filtering software for retail on the web. Most of the technologies out there are based on the theories of Claude E. Shannon , a visionary whose landmark works have been published since the early 1950's. He passed away a few weeks ago, and I think his work has yet to be fully explored or understood.
People know what they are doing.
There's a sucker born every minute. They just need to be educated. I want to get more value back in products than I'm giving you in money. I want a bargain, but I'll tolerate an even trade. I know that some products in my shopping cart are discounted and some are not.