I will live in Australia and would like to know if I can take my drone into the country. I have the invoice for the product, but I fear that the equipment will be barred at the airport. Are there any laws about it?
I think your fears are just that .. fears.
The official CASA website: Flying drones/remotely piloted aircraft in Australia has several sections about flying drones in Australia. And (for example) under the section "How are you planning on flying your drone?" => "For fun" its states
You don’t need approval to fly your drone for fun.
There are however other choices for if you are flying commercially depending on whether your drone is under/over 2kg.
And from a quick google of "import duty drone Australia" there are several hits coming back saying that that is 0%, so I wouldn't expect any hassle at Customs, especially as it's your personal belongings.