I’ll document here manipulative techniques and real-life examples of them in action. May you be more aware and avoid doing the same.
I’d love to hear your suggestions or stories and have them added to this page. Don’t hesitate to comment!
Decoy Effect

Wikipedia: AKA Attraction Effect or Asymmetric Dominance Effect, is the phenomenon whereby consumers will tend to have a specific change in preference between two options when also presented with a third option that is asymmetrically dominated.
This article by The Decision Lab goes into it in more detail and even discusses how to avoid it.
Who’s guilty of it? Almost every large company, including Starbucks, Coca-Cola, Apple, and various software companies.
Price Discrimination
Charging different prices to different customers for the same product or service, not based on the cost of providing it, but based on the customer’s willingness to pay.
Here’s an illustrative example I recently saw from a friend:

Sadly, in oligopoly markets dominated by a handful of suppliers, retention pricing is the norm, and there isn’t much that consumers can do when all the providers are playing the same game. In Canada, all the major telecommunications companies (and their subsidiary brands) do the same: Bell, Rogers, and Telus.