There is no cost for a debtor to file a bankruptcy petition.
If a debtor is discharged from bankruptcy without paying any payments toward their debts, no fees are payable.
Where a bankrupt's trustee collects (realises) money through either the recovery or sale of assets or through contributions, fees and percentages are payable to the Official Trustee. The administration charges are set out on the Fees and charges page of the AFSA website.
Private trustees' fees are based on an hourly rate and can be very expensive. A small debt may be dramatically increased if a person is made bankrupt unnecessarily.
A creditor who issues Court proceedings to make a person bankrupt must pay a Court filing fee as well as meet the cost of preparing the documents, and appearing in Court. This cost is recoverable from the bankrupt's estate, but only if there are sufficient assets available to meet the claims of creditors. The cost can be significant, and it is prudent for a creditor to undertake investigation of the debtor's assets prior to spending money on a creditor's petition.