I've been impressed with the SainSmart PLA filament from amazon: http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=sainsmart+1.75mm or http://www.sainsmart.com/other-1/3d-printing-material.htmlhttp://www.sainsmart.com/other-1/3d-printing-material/pla-filament.html.
It is certainly not the cheapest out there at $50/kg, but the print quality is great and I have not had any issues with it jamming. I have printed a roll of Green and a roll of Red, no issues on either.
The green is a nice light green, see here:
. The red is a deep red, much better red than the ABS I purchased from Leapfrog which was closer to orange, see here: