Kitebike said..
Kite surfing is a fairly expensive sport, more so in Australia than other parts of the world...
How so? Kites and boards arent that much more expensive than they are in Europe or the US (from the O/S online sites I've checked out anyway). Of course lessons will cost you more here, especially than in places like the Philippines etc but at least it's a one off - you'll soon get over it and forget about that...
Compared to a lot of other water sports eg: Water skiing, wake boarding, sailing, boat fishing, even scuba diving - I reckon it's cheap as.