Most personal 3D printers require plastic filament of some kind or another. Recently some manufacturers have moved to use factory-certified cartridges, but many devices still can use "any filament" that meets the necessary dimensions.
There are several online stores ready to sell you such filament, some trying to distinguish themselves by offering wider varieties of unusual filament colors, for example. A new shop, FormFutura, offers something particularly unusual: wood filament.
We've seen wood filament before, in fact the same species, LAYWOO-D3, but now it seems to be offered at a third party site. The filament obviously isn't simply 100% wood; it's a mix of wooden fibres in a binder. They say:
After printing, your object will look and smell like wood and it can also be handled like wood. After printing you can cut, grind and paint your creations similar as you can do with wooden objects.
So for all intent and purpose, it's wood. And you can get 250g (about half a pound) at FormFutura in 3.0mm or 1.75mm sizes for €20.95 (USD$28).
While you're at FormFutura, you might also check out their interesting combo packs; the "B&W Packs" and the "Fun Packs" include some great colors. We also understand they may be considering offering Nylon filament in the future; watch for that.
[UPDATE] We've been informed by Rien from FormFutura that the 3.0mm Wood Filament actually sells for less: €18.95 (USD$26). And there's even better news: those outside of the EU do NOT have to pay taxes, which are otherwise included in the price. Without taxes, the 1.75mm wood filament sells for €17.31 (USD$23.50) and the 3.0mm for €15.66 (USD$21.20).