We’ve found a rather inexpensive source for 3D printer filament: FoxSmart.
We’re not certain how they can price their filament so low, but it is quite a bit less than other options. Typical pricing for a kilo of PLA or ABS filament these days is around USD$30-50 for a spool, but FoxSmart is selling 1kg spools for only USD$18!
As a comparison, MakerBot’s online store offers a similar 1kg spool of PLA for USD$48, more than 2.5x the price of FoxSmart’s.
Even better, they are currently including their “Filament Creator Kit” with every filament order. What is it? It’s a sampler kit with seven 25-foot (7.6m) filaments in different colors. [UPDATE: to receive this offer, you'll have to use the coupon code "FREE3DPLA" when you checkout.]
How do they do this? They say they purchase directly from the factory and cut out intervening markups typically applied to consumer products.
However, we must issue a caution: low cost filament sometimes is of unknown and potentially inconsistent quality. Some cheap filament is made using toxic materials for coloring or has inconsistent diameter, which can cause print failures. We do not know the quality of FoxSmart’s offering, but the price is low enough to give it a try.