Polylactic acid, or PLA, is the most common 3D printing filament, and it's the easiest to use. Unlike most plastics, it's made from corn starches so it's nontoxic and, in theory, compostable ...

My practical 3D printing advice is simple: if you're buying a new 3D printer, get one with a filament runout sensor. If you don't have one, see if it can be added and invest a few bucks to upgrade ...