Here is an interesting article I read recently: Product Sabotage helps consumers. The title is a bit misleading; this "product sabotage" doesn't really help any consumers.
They use Starbucks (mmmm, Starbucks) as an example of what they mean. If you go to Starbucks, there are a lot of things that you can buy that are not on the menu. For example, a "short" cappucino is a tiny little cheap drink. A lot of people would probably only want this Tim Horton's-sized inexpensive drink rather than a larger one, but they don't know it exists, so they buy a bigger one. The small one is still available though, for the people who know about it and buy it because they can't afford the big drinks.
The idea is that people who can afford more expensive items buy them, and the poor bastards who can't will still shop at Starbucks because they're motivated to seek out the poorly advertised deals. So Starbucks gets both of their business.
I don't think this idea is inherently unethical on the surface. People who put the work in to find "deals" will get cheaper drinks. Good for them. The rich people can buy expensive drinks and the poor people can still enjoy the cheap drinks. I fall into the latter category, so I already knew about the Short size (but I don't buy that shit...I need more coffee than that to function normally). Rich people pay the normal price, and poor people can get a discount.
At least, it doesn't seem unethical when you say it that way. But what if you say it this way: Poor people pay the normal price. Rich people get tricked into only ordering off the menu and paying an inflated price.
This is called "framing" in psychology. There are different ways of saying the same thing that will differ in how they are percieved. Another example is getting a 5% discount when paying for something with cash (vs. credit card) at a store. Yay? But what if, at another store, you are charged a 5% fee to use a credit card? It's two ways of saying the same thing, but you'd probably be happier shopping at the former store than the latter (no matter how you're paying).
I guess my point is that you gotta think carefully about "deals", because they can be framed in two ways: paying less for the deal, or paying more for the non-deal. Corporations are intentionally exploiting these quirks in the English language and human reasoning to trick us into buying things for more than we have to. In other words, don't let the man fuck with your mind, man.