Buyer in possession

The PPSA and PPSR provide a means of securing the buyer’s obligation to pay. This scenario usually arises when goods are sold but it can also apply to services (for example, if software is being written and transfer of ownership or copyright is postponed until payment is made). In the old days, retention of title clauses had the same effect – “you do not get ownership of the goods until you pay” – but under the PPSA that does not work unless:

The buyer agrees in writing to grant the seller a security interest in the goods sold (collateral) which includes its proceeds (money).
The buyer registers that interest by filing a financing statement describing the collateral – called “perfecting the security interest”: cost $3.

Some very good advice here from Richard Osborne at Homebizbuzz.