There’s no need to be conned by a slick salesman into buying a computer for more than $500 these days.
Today I bought a fast, reliable, authentic computer for only $399! It’s second hand, but it’s totally refurbished and you wouldn’t know the difference.
Companies that sell ex-government computers and ex-corporate computers are all over Australia, and you can find them by typing in ‘ex-government computers’ or ‘computer recyclers’ into a Google search. The most popular stores will be at the top of the search results.
The shop I visited today was Brisbane Computer Recyclers.

Computers can be very affordable!
But of course I already had a monitor (the screen), mouse, speakers & keyboard etc.
You should be able to pick these items up very cheaply also from the same store!