What if people stopped buying stupid unnecessary shit?

What if people stopped buying things like stuffed animals, decorative centerpieces, 100 pairs of shoes, expensive jewelry, toys that will break or go missing within a week, and other stuff? What if people stopped throwing their money away on stupid shit and only bought 100% necessary items? The economy would change dramatically, but how would it affect us citizens? With everyone suddenly living frugally, how would businesses be affected? What would start to happen over time?