Australia is enormous, sun-blasted and weird in the best way. You'll bounce between rainforest waterfalls, coral gardens and red desert highways, and the food alone is worth the flight. Spring (September to November) and autumn (March to May) sit between the wet season up north and the peak-summer crowds down south, so the weather is friendly and the prices are saner.
The flights are the expensive part, but the good news is that a $1,200 trip is doable if you stop trying to pay it all in one go. Spreading the cost across a long interest-free window is the move most travelers don't consider until it's too late.
Honest caveat: 0% intro APR is a deadline, not a discount. If $1,200 is still on the balance when month 15 ends, interest starts accruing on whatever's left at the card's regular APR. Treat $80 a month as a non-negotiable bill until the trip is fully paid off.