If you get to the point of having an
MRI done, there is financial help for that
cost through the MSAA group. They will pay for diagnostic MRIs.
Another thing, try to negotiate the costs of your tests in advance to get the cost reduced. If you can be seen/treated at a teaching hospital or not for profit hospital, often times the cost will be prorated depending on your income. Please look into all these possibilities.
Welcome to the forum. I hope you will come through often.