What is the power of the wind turbine? How high is this tower?
If you asked about the basis, what basis would you use? Is it gravity?
If you mean the engine room chassis, suppose it is two megawatts, suppose it is designed by us, then: it weighs about 15.9, and it needs hundreds of thousands.
If you are talking about the foundation, assuming it is 2MW, the amount of steel used will be dozens of tons. It's hard to say what the cost is.