Translation:Is the cost of studying abroad in Australia high?
Personally, I would translate your version as either "很贵吗" or "要花很多钱吗". If both ways exist in either language, its because both languages differentiate between the meaning, and thus the sentences shouldn't be interchangeable, though they may be used in similar situations. By this standard, even my "很贵吗" is veering a bit too far.
The 'studying abroad in Australia' grinds my ears - the word abroad is redundant. Also, the meaning of 'abroad' is implied even without using the word. Either you live outside Australia and then it's obvious that it's abroad, when you ask about it, or you live in Australia and then you do not use 'abroad', because it is not, in fact, abroad. Except, of course, if citizens of one Australian state would refer to other Australian states as 'abroad', in which case this sentence would make sense as it is, but that idea sounds funny to me and, additionally, I would highly doubt you can find that kind of catch in this course.