Hi, the extra $10 might be the shipping fee(Minimum shipping fee USD 10, calculated at USD 3 per kg).
There is also a filament bulk sale discount:25% OFF on 4+ rolls | 30% OFF on 6+ rolls | 35% OFF on 10+ rolls. Learn more details here.
No… that’s only the conversion from USD to AUD for the rolls…shipping is on top of that and converting that to AUD makes it even worse. Typical pricing in Australia is $24-30 so even at the higher price that’s still around $5 per roll which adds up.