I’m from Australia, and think it’s a great place, but i really don’t think that spending a semester there taking a couple of classes is going to constitute “crucial” experience for the average American college student, nor is it likely to give them a “competitive edge” in “an increasingly global environment.”
For all of our funny accents and our backwards seasons, Australia isn’t that different from the United States, and a few months in an Australian university won’t be that different from three months in an American university. This is not to say that it wouldn’t be a great experience, and i’m sure the OP would have a great time. But it’s not going to make or break the rest of his career.
Before i came to live in the US, i spent a few semesters as a TA for my undergrad university in Sydney, and i had a total of about 15 US exchange students during that time. They all seemed to really enjoy themselves, although the main attractions seemed to be (a) the weather and the beaches (quite a few of them were from U. Wisconsin, and Cornell, and other cold places), and (b) the fact that the legal drinking age is 18. I know that quite a few spent most of their semester lying on the beach in an alcoholic stupor.
To the OP:
I’m surprised that the price for your trip has actually increased recently, because the Australian dollar is again very weak compared to the US dollar. When i was back in Australia in July, the Aussie dollar was strong and the exchange rate was almost 1:1, but now the Australian dollar is back down around the US67c mark. Even with the exchange rate, though, Australia’s a pretty expensive place, especially big cities like Sydney, and if you want to go out to bars and restaurants it can eat into your finances very quickly.
You could consider The Tao’s Revenge’s suggestion of a working holiday (here is the one that applies to US citizens), but you will need to show evidence of health insurance, a return plane ticket, and at least $A5,000 to support yourself. They can, and often do, ask for evidence of this money before they let you in. These Work and Holiday visas are not designed as proper work visas, and you’re not allowed to work full-time.
Also, while picking fruit might sound like fun, most agricultural labor is pretty backbreaking work. I spent a bit of time working on cotton farms when i was in high school, and i have friends who’ve done work like cherry picking, and it’s all pretty physical labor. And, in fruit picking at least, you get paid by the amount rather than by the hour, so if you can’t keep up the pace you won’t earn much money.