As in a typical standard contract:

PRICE: The price is set out in the schedule. It must be certain as consideration is an essential term of the contract. For example, “Agreed price is $200 000 payable as 10% deposit and the balance over 5 years” is void because of uncertainty. That is, how the balance is to be paid is not specified, for example, does it mean yearly or monthly? If interest was to be charged, it should have been stated. However, for a rural property “$1000 per hectare” is valid consideration where the area of the property is expressly stated elsewhere in the contract. If the area was not stated in the contract, consideration would be uncertain and there would be no contract.

Typically, 10% deposit is paid on contract and the balance at settlement. The deposit is held in the agent’s trust account.