Prime Minister Malcolm Turnbull says the submarines are essential and will help protect Australia. But what else could the $12.5 billion price tag of a submarine pay for?
$1000 cash for everyone
$12.5 billion could fund $988 payments - akin to the Rudd government's stimulus handouts - for the 12.6 million Australians in the labour force.
Five cutting edge hospitals
According to the latest figures, the new Royal Adelaide Hospital will cost $2.1 billion to construct.
Forgiving a quarter of all uni debt
The total Higher Education Loan Program (HELP) debt is projected to reach $59.7 billion in 2016.
Reduce the budget deficit by a third
As of December, the deficit stood at $37.4 billion.
According to the Centre for Independent Studies, $12.5 billion could address one year of bracket creep, the process that sees inflation push wages into higher income tax brackets.
Complete reversal of record foreign aid cuts
From 2014 to 2018, the government is overseeing $11 billion in cuts to foreign aid, the largest reduction in Australia's history.
....and finally six years of Gonski education funding