There is a guy selling a stock of 500 1kg rolls of 3mm PLA and ABS from 3dfilamenten.nl in the Netherlands, at less than $7 a roll.
I bought 24 rolls.

Here is my comparison to Colorfabb and 3DOM filaments:

Colorfabb
Layer-layer adhesion: 4/5
Flow: 5/5
Smoothness of print: 4/5
Accuracy: 5/5
Color quality: 5/5
Flexibility: 4/5

3DOM
Layer-layer adhesion: 5/5
Flow: 5/5
Smoothness of print: 5/5
Accuracy: 3/5
Color quality: 5/5
Flexibility: 5/5

3Dfilamenten
Layer-layer adhesion: 4/5
Flow: 4/5
Smoothness of print: 4/5
Accuracy: 5/5
Color quality: 5/5
Flexibility: 2/5