How much did it cost and in comparison how much a regular temple construction of the same magnitude would cost?

Construction of the temple in traditional/alternative way may reduce cost from 10% up to 45% but first o all everything depends on your home work. Get your data straight before you venture into temple project. Make sure you get honest suppliers of materials who can continually supply materials according to your needs. See which materials are easily obtainable (that may even influence design of your structure). All this will reduce your cost. If you live in desert like, arid area where wood is scarce and expensive it doesn't make sense to use it as your main building material.