We all know it's happening, but that doesn't mean you should let your guard down: Stores want you to make impulse buys and spend more than you originally planned.

Who doesn't realize that candy, sodas and magazines are stacked right next to the checkout to entice you to spend a little more before you leave? That's the easy trick to spot. Here are others:

ATTACK THE SENSES

If your mom said, "Don't go to the grocery store hungry," she was onto something. Stores tend to turn your senses against you, subconsciously and continuously attacking your sense of smell and sight to get you to buy. Whether a grocery or department store, the smell of fried chicken, baked goods and hot-selling perfumes permeate certain aisles to get you thinking of spending.

What to do: Eat before you arrive, have a list in hand, and get in and out as fast as possible.

AISLE DESIGNS

Of course, the whole store is a giant maze engineered to get you to see as many products as you can before you can reach that tub of butter or roll of tube socks you were after. The newest, highest-priced products will sit on eye-level shelving to grab your attention. They will be well-stocked. The older or lesser-priced goods will often be on shelves that are harder to get to, and don't expect those items to be as well-stocked. The end of the aisle is where stores love to put new items, sale items or popular items they want to sell more of because they know most shoppers stop there.

What to do: If you want an older product, off-brand product or a cheaper product that is not in stock, do not compromise and buy the higher-priced, in-stock item. Ask a clerk or manager whether the item you want is in a back room waiting to be stocked. If not, ask to find the product at another store location. If you still can't get the lower-priced item, check a competitor.

CART GUERRILLA WARFARE

Shopping carts are at the front of the store so you have a big bin to drop lots of items into. It's like the big dinner-plate phenomenon: The bigger the plate, the more likely you are going to fill it up, even if you're not hungry. Same thing with a big shopping cart.

What to do: Go for the smaller handheld carriers if you are not shopping for a lot.

TOYS AND OTHER DESTINATIONS

If you've ever shopped with a child, you know you're going to have to stop at the toy aisle. That's why it's usually located at the back of the store, so you have to pass as many other products as possible as you trek there. The store hopes you'll impulse-buy all the way there and back. Same with electronics and furniture and other high-profit items.

What to do: Bring a toy with you or have a new (cheap) one at the ready before you go in, taking your child's interest at visiting the toy aisle away -- or at least diminishing it. If you don't have the discipline to go to the back of the store and get out as soon as possible, grab just enough cash to make your purchase, leaving your credit card behind. It's impossible to buy what you don't have enough money for on hand.