Most of the products of major necessity are always located at the back of the supermarket, this is structured so you walk through all the premises and, therefore, watch more products and “wake” your interest in some.
The most expensive products are always placed at eye level to be more accessible and easier to choose.
Most of the prices always end with a number 5 or a number 9 ($19.85 or $19.99), this is just to look cheaper. We look the number from left to right with a downward attention level, in other words, we tend to look the first digits of the number to evaluate the convenience of what we are buying. People associate the numbers that end in 9 with offers or discounts.
When we finish our grocery list, there are always chocolates, candies and beverages placed in the cashier line; this is structured for you to feel like having them while you are waiting, and it is likely that you buy some of this.
You may not remember which was the last song you heard at the supermarket, but it may influence in your pace. The supermarkets usually reproduce slow music to slower your walking rhythm, indirectly making you stay longer, resulting in a better view of the shelves and products, which will end up with the consumer purchasing more products.
Most of the consumers only remember the prices of 20 essential items, also known as KVI (Known Valued Item). These items have low profit margins, nevertheless, this low profit margin is compensated with the high profit of other objects.
Free samples is another common strategy to enhance the sales income. Investigations demonstrate that 75% of people accept free samples. These samples may open your appetite and make you purchase the product in full.
References:
http://www.bbc.com/mundo/noticias/2015/09/150807_iwonder_secretos_supermercados_finde_dv