The term two by four (2x4) refers to the rough cut dimensions of construction grade lumber. However, the typical 2x4 purchased at a lumber yard is actually 13/4" x 31/2". Nonetheless, the term 2x4 persists.
vCalc regularly surveys the websites of big box DIY retailers like Home Depot, Lowe's and Menards for pricing. The most recent surveyed 2x4 price data is:
All prices are in U.S. dollars and based on searches of nationally advertised prices from the provider's web sites. The data is refreshed every few months.