[1] Costley was known among the "old identities" of Auckland as a man of rather penurious and retiring habits, who had acquired property in the early days, which, with the growth of the city, had become of great value.
He purchased property at a time when it was empty scrubland and as the town of Auckland grew he quietly expanded his landholdings.
It is possibly significant that money was spread across a number of the various religious denominations including homes run by the Anglican and Catholic Churches and inner city Missions and shelters administered by the Methodists and others.
Since Costley's death an unsigned draft will has come to light which showed that he had long contemplated the application of his wealth to charitable purposes.
He died in Auckland on 18 April 1883,[3] and was buried at Symonds Street Cemetery where the Costley Trust erected a monument to his memory.