I dropped by my Kroger store yesterday to pick up a jar of peanut butter. Twenty-five minutes later I checked out with $38.78 worth of goods – mostly deeply discounted Christmas decorations. My bad!

On the way home, I was so mad at myself, I seriously considered returning the items. I have no place to put them!

The whiny voice in my head responded “but they were so inexpensive, and I really needed that big twig raindeer.”

“Like heck,” retorted my more logical self. I guess I can dress the deer up as the Easter Bunny.

“Two-thirds of what we buy in the supermarket we had no intention of buying,” says consumer expert Paco Underhill, author of Call of the Mall.

He says supermarkets not only rely on such behavior; they encourage it. Every aspect of a store’s layout — from the produce display near the entrance to the dairy case in the back, to the candy at the register — is designed to stimulate shopping.

Take produce – your grocer is selling “fresh.” But warning: you must reach to the back and dig for the freshest items. Retailers usually have the oldest merchandise in front or on top, since they need to get rid of it quicker.” Ditto for meats and dairy. Also, buy produce during the week since most deliveries come in Monday through Friday. Logic tells me Sunday evening is probably the worst time to do my shopping.

Then, there are the staples- usually placed at the back of the store so you have to walk past all the enticing goodies to get there. I went to buy peanut butter but had to go by six aisles to get it, spotting the reduced Christmas decorations in the meantime. Oh, I also bought a bag of alphabet pasta – Why, but why?

“They were so cute,” argues my whiny side.

“Cute don’t pay the electric bill,” retorts my logical side which often uses bad grammar.

See how that works? I would have been better off stopping at a convenience store – granted, I would have paid about 75 cents more but saved $35 bucks in the meantime.

Watch out for end of the aisle displays – they don’t necessarily say “discount.” If it’s on sale, believe me, it will be prominently marked.

On the other hand, you may find better deals on health and beauty products in a supermarket than at a drugstore. There is a large profit margin on these products, which supermarkets are sometimes willing to generate more traffic. Mote they are often located next to the pharmacy, hoping you will pick up some hair conditioner while waiting for your prescription.

The placement of items on store shelves is not haphazard. Typically the top shelf displays regional and gourmet brands. These smaller brands usually don’t have the budgets to pay for more favorable placement.

The bulls-eye zone is front and center and right at eye level unless you’re a toddler or a basketball player. It’s the best placement, and the manufacturers have to pay (the supermarket chain) for it. There’s no advantage for the supermarket to show you the lowest-priced item in the most effective spot. So here you tend to see higher-priced items or items with the highest markup. Secondary brands hoping to benefit from being shelved next to the leaders also pay for placement in the bull’s-eye.

Always look below the bull’s-eye to find similar products for a lot less. Store brands are a great idea. The same manufacturer that makes the branded product often manufactures the house brand.

Buying in bulk may not be such a good idea. If you have 64 rolls of toilet paper, it isn’t really a bargain. It’s money out of your pocket that could be earning interest in the bank instead. And the more you have, the more you tend to use.

So happy grocering. But my advice to you is stay off the aisle with Christmas items. All that discounted wrapping paper and decorations must be stored somewhere and they’ll be dogeared and look “used” come December.