Some people are susceptible to alleged price reductions. I am susceptible to location. If a location can cast its spell upon me and transport me to another time then I had better hide my cards.
These are two very different areas. The first is Bath that transforms me into Mr Darcy. In my Darcy personal I am already rich so I have to remind myself that I am not. The second photo is the City where the real rich guys hang out. I must take care not to imagine I am one of them.
A supermarket will place it's most profitable lines immediately ahead of us and slightly down. This is in our direct line of sight and most people look no further. Above and below we may find greatly cheaper products in less appealing packaging. The difference in quality is often less than the difference in price.
Be wary of 'buy one get one free' offers in perishable goods. These often turn into 'buy one, throw one away' offers.
Never buy confectionery at the checkout and never (ever, ever, ever) get a child in the habit of demanding you do so.
Retailers employ the finest psychologists in the world and their aim is to make us into impulse shoppers- the most profitable kind of shopper.