G'day Chinaman Gold welcome to PA great plan you have :Y: it's a great family activity. As for the machine choice it can be a mine field so to speak, so worth giving thought to the following hopefully others will jump in and offer their opinions as well.
1 Dedicated Gold detectors, how often are you likely to use the detector, how far from any gold fields are you. If your in Melbourne try hiring a SDC2300 and head to the gold fields. If you are looking to buy your first gold detector these are worth the money and retain resale value.
2 Coin and Relic detectors, if your in metro Melbourne these machines can be used at parks and beaches. It only takes one decent find (jewellery, gold with diamonds) to either pay it off or close to. As far as a find paying off equipment goes coin and relic machine are better placed than the mortgage breaker nuggets go not to many have achieved that dream but we try.
As far as making a living off prospecting goes most would say don't give up your day job. At the end of the day this hobby is great for getting outdoors and away from home. All the best when you do decide on your weapon of choice.
