No, no, we don't mean "Green". We mean "Green" as in environmentally responsible. We've been looking at filament supplier GP3D, who sell a decent selection of ABS and PLA plastic filament in 1kg spools.
Their pricing is decent (USD$32-44 per kg depending on the color and choice of material) and their color selection is not bad, either. You can choose from among 24 different options of material and color.
But how is it green? GP3D is a subsidiary of Green Project, Inc., who:
Strive to provide you with a premium filament choice when it comes to 3D printing material. Our products are extensively developed by the best engineers, and passed through heavy quality systems such as ISO 9001. Product development is our strength and that is what our customers look to us for.
The Green Project takes discarded inkjet printer cartridges and "gives them new life". Apparently they want to do the same for 3D printer filament.
We're not exactly certain how they provide greenness, though. Perhaps they recycle spool holders? Do they accept used prints and recycle the plastic? We could not find evidence of either on their site, so they may not be as green as stated.