Renewable energy resources, like the wind and the light and heat from the sun are basically endless and you can surely use them to your advantage and provide electric power to your appliances almost for free. The added bonus is that you don’t create any toxic waste either, so you really can use renewable energy resources.
So, in order to harvest that energy you need specific equipment. For example, if you want to create electric energy from the sun’s light you need solar panels. For these to actually transform the light into electrical current, you need to have additional hardware that can actually send the electric current to batteries and store it there until you are ready to use it. You can also use some electric motors to turn the panels towards the sun or do this by hand, so you get the most out of your setup.
Wind turbines are also used to harvest the wind’s power and you also need additional hardware to be able to use the electric power generated by the turbines. Usually, with all renewable energy resources harvesting systems, you also get a pack of batteries to store the energy there if you don’t use it as soon as it is created. This is why the systems cost so much, because you actually need to use those batteries. They are large and can store massive amounts of electricity in them until you need to use it.
There are, of course, other ways in which you can use renewable energy resources. You can buy a system that uses solar heat to warm water up and use it instead of wasting money on natural gas or other expensive methods of heating water. Those systems are actually worth their weight in gold, but you can have one for a couple of thousand dollars and never pay for heated water again.