I build and buy depending on what it is, my time frame and enjoyment of building a certain style. Removing the tools and supplies from the equation except for lumber and hardware; you can build a dresser, for example, for less than I would charge you to build a dresser of like quality. You can build that dresser for less than you can buy one of like quality. You cannot build it for less than a commercially produced product but, you can miss out on the enjoyment of building it. My .02
P.s. Do not let anyone who influences your tool and material buying see this thread