For hobby/experiment use decomissioned panels from upgaded farms, sometimes you can get two years old panels that were swapped for more efficient ones for a fra

For hobby/experiment use decomissioned panels from upgaded farms, sometimes you can get two years old panels that were swapped for more efficient ones for a fraction of the original price. For setup with batteries there is (depending slightly on local electricy cost) no long time break-even - the battery deprecation due to discharge cycle costs more than electricity from the utility.