We Americans really have a hard time not buying things. Nothing in particular, just things. It's no wonder we don't feel that we can spend money on quality organic and local food, or on alternative energy, or clothing that is more expensive because someone actually made a livable wage to produce it. We're spending all of our money on little plastic things or more clothes than any one person needs.
We've tried to break the buying habit, but it is difficult. We've grown up purchasing things we don't need, either because everyone has one or we are depressed and need a pick-me-up. So we've installed the "take something out" rule to curb our consumerism. It works like this: for every thing we bring into the house - whether from a big box chain or a garage sale - we must remove one item from the house. Even things like socks have to replace something (often other socks, with holes in them).
This simple rule has changed our purchasing habits completely. Sure, a shirt looks good on the rack, but then I have to get rid of one of my other shirts, and I like my other shirts. Decision made. While we slip up once in a while, we generally hold each other accountable to this rule. We can finally leave a store without $50 of crap we don't need. We've taken our power back! You can too!