1. They hand out free samples. You used to only see it at Costco, but a lot of stores do it now. It makes you more likely to buy something you wouldn't normally buy. And they tend to hand out fatty, salty foods that taste good. Which makes it's harder to say no.
2. They make you use giant shopping carts. Which makes us think our cart isn’t very full, so we keep adding stuff.
3. They put expensive brands at eye level. When something's front and center, you're more likely to buy it. So look down or up, and you might save a few dollars. That's where the cheaper brands tend to be.
4. They hide the essentials at the back of the store. Bread, milk, and cheese are usually near the back, so you have to walk past all the other stuff to get there. Which ups your chances of making an impulse purchase.
5. Ads that say things like, "Ten for $10." So then people assume they NEED to buy ten of something to get the deal. But if you look closer, that's not always the case, and you still get the same deal if you buy one or two of them.