Treloar Reality had blocks of land for sale in Gymea in late 1966 for just a seventy pound deposit ($140). The lots were in First Avenue and Yarra Burra Street and appears to also include Conjola Place and Cobargo Road.
A Google Streetview reference to the area today is available here.
Source: Treloar Reality Pty. Ltd. 1966. "Sensational New Release !!!" (Advertisement). The Sun, October 14, 63.