Circling the Prey

A quick tactic for avoiding the urge to put something extra in your cart:

When you get to the store, do a circuit to find all the things you've come for before you get a cart and place the items in it. You'll then be able to see if there's anything that you missed that's at a serious (read, valuable) discount. Once you've done your circle, get a cart and place the items you wanted in it.

The idea isn't to have a chance to pick up more things, it's to have a second sober thought before you decide to finally purchase. The more checks an item has to go through, the less chance it'll pass - and the higher the chance that only the highest value items will make it home with you.