You can buy mushroom kits from bunnings at times. They are fairly small but are good to get an idea of how to grow them. You can also use them to seed a much larger mushroom bed. You can also get mushroom spawn from mushroom growers. It usually comes in a bag and is grown on corn kernels.
You can use just about anything as a mushroom bed, half barrels are good. Get some straw and manure (chook poo is good) and mix it with the straw. Keep it in quite moist and let it compost down for a few weeks till it is squishy. Add mushroom spawn and then top the barrels off with wet peat moss. Put the barrels in a dark humid spot, not too cold and keep the peat moss moist but not sopping wet.
Usually take a couple of weeks for the spawn to grow up through the moist peat moss and start to pin on the surface. Once the pins start to show you will have mushrooms popping up like......well like mushrooms
