How to work out land price?

How do I find out the average/range of the price of land? I am interested in the suburb ferndale in western australia.

 

Dont really understand your question but working out land value in a developed area is harder than an undeveloped one
Best way would be to grab as many sales as you can in the past year of similar houses on blocks of varying sizes and work out an average price per sqm
Then depending on the area you would still have to take out some $ for the cost to build a house
In regional areas land is roughly worth what a 3bed house (weatherboard ) is less 170 - 200k

In citys there are almost 3 tiers

In really good areas land is valued at what an old house (non character) sells for , ie the house adds no value to the land

In ok areas there is generally some discount on land from a decent house - 100k- 150k

In outer or house and land areas your looking at land being around 150-250k less than finished product and the land is normally of a smaller size than in older suburbs.
Obviously if the land is 250k less you can make a development play and make 50 - 70k on the way through and sell it after construction.