Most assets your non-profit organisation sells will be subject to GST; however some will not, for example sales of houses or flats used predominantly for residential accommodation.
If you sell assets such as motor vehicles, property or machinery, you must account for GST on the sale.
This is the case unless you sell the asset for less than 75% of its original cost or for less than 50% of its market value and you are:
an endorsed charitable institution
a charitable fund’s endorsed trustee
a gift deductible entity, or
a government school.
This means that you do not charge GST on the sale price and you should not issue a tax invoice to the buyer.