If traditional printers use ink and toner cartridges, most commercial 3D printers use plastic filament spools to create the objects you want. These filaments, however, are typically made from plastic pellets, so an Ohio company called Sculptify thought: "Hey, why don't we make a 3D printer that uses pellets straight up?" Thus, David, a 3D printer loaded with open source software, was born. David can print objects using a number of soft and flexible materials, such as Polylactide (PLA) and ethylene vinyl acetate (EVA), though it can surprisingly use wood, as well. Since pellets are usually much cheaper than filaments (according to Sculptify, a 2-pound bag of pellet costs around $18, while a 2.2-pound spool costs roughly $48), you'll be saving quite a bit of money.