What do the models cost?

This depends upon many factors in what is involved. Most of the factors above dictate the cost as well as hours to build. It can vary from between several hundred dollars up tens of thousands. An example would be the TENIX 56M SAR Craft which cost approximately A$400.00 each, up to something like the interactive model of HMAS SYDNEY, which is valued at approximately A$40,000.00.