What is max amount that your budget will stretch to? I'd prefer to stick to known and proven brands, like some of the lower end Teknetics detectors for a starter detector. The bottom of the range Teknetics Eurotek or Alpha 2000 represent better value than the Jaycar one, the Eurotek only costs $199, and is probably cheapest known brand detector on the market at the moment, other than the Tesoro Compadre.
I'd love to recommend an Ace 250 or 150, they are great fun detectors, but are ultimately expensive for what you get when bought new. Pick up one second hand for around $200-250, and they are great to start out on.
The Jaycar unit might be ok to have a bit of fun with initially, but pretty soon you will probably have wished you put that money towards something a bit better. I was much like yourself in my youth, looking at cheapy detectors, trying them out, then wishing I had just saved another $50 to get something half decent. The Jaycar detector also takes a shed load of batteries for a little detector, plus no mention of water resistant or proof coil, and very light on features.
Even if they do half work, the build quality just isn't there, and the cheaper machines tend to screw up after a short period of time (especially those light aluminium shafts with no pins to lock them in place).
Here is a link to the Teknetics Eurotek to see what you get for $199 - a bucket load of features for a beginner detector. I think Aussie Detecting & Prospecting in Bendigo are the current Australian dealers for the Teknetics brand.
http://tekneticst2.com/teknetics-eurotek-metal-detector.htm