If you're into saving money, using as many solar powered ideas as you can find makes sense. It can be fun to find different ways to get the sun to do for us what we now pay to have done. If you haven't tried these, they're worth thinking about.
Passive solar powered oven
It took me a long time to decide to spring for a solar oven, but I'm glad I did, not only for the money it's saved, but for the pure pleasure of cooking a pan of cornbread or soup in it. The food is delicious and it never burns or dries out.
The concept is simple: A black box to absorb heat, a see-through cover to allow the sun in and to trap the heat as well as to keep the food safe from dirt, bugs and animals. There are many variations on the basic plan, from elaborate solar kettles to cardboard pizza boxes. Aluminum or mylar can help reflect even more sun rays into the box to raise the temperature a little more. You can cook anything from hotdogs to cake in the right solar oven.
Passive solar powered dehydrator
A simple tray with a mesh bottom can be put together by almost anyone. Put the food on it, cover with a cloth and set or hang it in the sunshine, or use your car. Just be sure that the mesh is food safe. Window or door screen are not. You may find a plastic mesh that's food safe or look around at what you already have. It doesn't have to be "mesh" as such, just something flat that will allow some air circulation. I have used a mesh type of no splatter lid, and although it was small, it worked fine. The ridged part of a broiler, if it has holes, will work. If you can't find anything else, go ahead and use window or door screen, but cover it with a cloth before putting the food on it. Cloth itself, when it's stretched tightly onto a frame, is good to dry things on. Use your imagination.
Passive solar powered food warmer
Again, use your car. Put your food, wrapped like you would a sandwich or in a covered container, on the dash of your car when it's in the full sun. It won't be long until it's warm enough to eat. Use this method to save honey that's started to crystallize, to thaw frozen soups from the freezer and to melt butter or to melt chocolate for dipping or any time that you would use a double boiler. It may be a little slower, but it's cheaper by far.