I got some 3mm PLA from an eBay vendor called globel_egrow. The spools are labelled "reprapper.com" and are 1.18KG each (about 2.5 pounds) and $34 each from the US including shipping. This is a very good price.
I just tried printing with the "natural" PLA yesterday - it works very well on my i3 with a 0.5mm nozzle - it's very nearly clear, moreso than the previous translucent stuff that I had, which was natural ABS. I have need for some translucent things and this will work well.
I need to print something with the other spool, which is fluorescent green, and assuming that's good, I'll probably get a few other colors - they have a glow-in-the-dark blue that's still only $34. Too bad they don't have any gold, I could use some.