Sharing was one of the virtues of Aboriginal societies. While Aborigines had little more than the bare necessities of life before the Europeans came, neither did they have anything resembling debt.
The real costs of doing anything, such as making a boomerang, were met at the time. The real cost of building anything is surely the materials and energies expended. Before the Europeans came the Aborigines owed nothing to anyone. The Aboriginal people are now part of a community whose major basic problem is a debt system, which the Aborigines did not help to create. It is bad enough that the white man has allowed himself to be enslaved by debt, but it is sinful that he should also inflict debt upon his Aboriginal brothers.