Knowing how much Marshmallows cost in Australia would be helpful...
Anyway, I'll assume it's somewhere in the $15-30 range. Quite a few good options from low end to high - the search function is your friend for individual reviews:
Soundmagic PL21 / PL30 (focalprice.com)
Meelectronics M9 (Meelec.com, not sure how much postage is)
ViSang R01 (about $31 on ebay)
ECCI PR100 (ebay)
If you're getting marshmallows for the bass, my choice would be the R01, PL21, or M9, depending on final costs for each. If you prefer a more balanced sound the PR100 and PL30, while slightly different, both provide good balance.