Visa Applications fees are rarely refunded.
The Application fee for the subclass 870 Sponsored Parent (Temporary) visa is quoted as $5,090 (for the 3 year visa), but only the initial part of the fee is lost if the application is refused. (I calculate the total fee as $5,240 from the official figures)
The first payment of $1,050 for the application fee is non-refundable.
The second instalment of $4,190 is only paid if the visa is going to be granted.
Consequently, the only amount risked for a subclass 870 visa application is currently $1,050.