To avoid this subtle persuasion, you could just stay out of stores and do all your shopping online. If that’s not practical (and let’s face it, it isn’t), go to stores with a list, and make a beeline for what you need, grazing results in touching, and you know what touching leads to.
If all else fails, my wife likes to put things in our cart while we do our shopping so that we can think about whether we really want it. This works surprisingly well for us. Ten or fifteen minutes later, the rush of picking up a new shiny gadget often wears off, and we can consider the purchase rationally. Often, it goes back on the shelf.