OfferUp

Founded in 2011 by Nick Huzar and Arean Van Veelan, OfferUp is the largest mobile marketplace for local buyers and sellers in the United States. The company offers free iOS and Android apps that make selling an item as easy as snapping a picture from your mobile device. Based in Bellevue, Washington, OfferUp was named No. 4 on Forbes' 2015 list of hottest startups.