In "The Silence of the Lambs", Hannibal Lecter and Clarice have this exchange:
Hannibal Lecter: And how do we begin to covet, Clarice? Do we seek out things to covet? Make an effort to answer now.
Clarice Starling: No. We just...
Hannibal Lecter: No. We begin by coveting what we see every day. Don't you feel eyes moving over your body, Clarice? And don't your eyes seek out the things you want?
Every year, billions are spent on advertising. To what end? To ensure that we see products every day, so that we can begin to covet them. The subtext of most advertising is that happiness can be bought (or, conversely, that no one will love you if you don't use the right products.) Even if we forget a particular brand name, we're exposed to that underlying message over and over.
People even put the lie to Lecter's assertion that we don't seek out things to covet, haunting online bargain sites (one rather honestly used to use the tagline "How to go broke saving money") or going to the mall for recreation.
If you want to spend less, covet less. If you want to covet less, limit your exposure to things to covet.