Earth4Energy is by far the easiest-to-follow guide among our reviews for building Solar And Wind Power System. We have tried to build the system by following the step-by-step instructions in Earth4Energy guide. Guest how much it cost us? We get some of our items from discounted shop and we were able to access all the parts needed for $189.20. And we manage to complete the setup and installation over a weekend. The Earth4Energy guide is so easy to understand and can be followed without any difficulty.