I get my PLA from http://www.repraper.com/ and have not had any problems
with it, it costs about $15 per Kg roll but as it is send from HongKong via
Fedex it costs about $15 per Kg for shipping so about $30 per roll.
(shipping time is about 2-3days)

Lybina in Bayswater are good for ABS, They don't list PLA on the site but
are very helpful and allow pickup, I would use them but use PLA. (shipping
via Auspost or pickup)

http://store.ozreprap.com/ is another supplier based out of Sydney, they
stock ABS and PLA at about $69 fer 2.3kg rolls and shipped via Fastway
($15)  (shipping time was 1 week)

Remember that filament does not like moisture. I left my PLA exposed for a
few weeks and it became very brittle and impossible to use (after using a
hair dryer on the roll it came good again).

[rob]