Inflation is gradually moderating. For some consumer goods, like gasoline, prices are outright declining. Gas prices are down 7.5% since last January, according to AAA. The reason has to do with basic economic principles. Also on the program: We discuss a nicely balanced economy (for now) and — from "Building Tomorrow," a collaboration by Marketplace and This Old House Radio Hour — hear about a clear, step-by-step "almost paint-by-numbers" approach to address the housing affordability crisis.