It's free, so why not? Why do we think that just because it doesn't cost us, or doesn't take a special appliance, it somehow isn't worthy of our consideration?
If it's free, and it works, use it! You'll save money, guaranteed.
Sure, you can spend a lot of money on solar panels and entire systems and eventually, you can save money. But if you can't afford that, or don't want to get that deeply into it, why not save money right now, doing the things you already do, just in a different way?
Try these out:
Need to heat some food? Before building or buying a solar oven, try opening a can and setting it in your car in the sun. It will warm to eating temperature faster than you think, even when the weather is cool. A solar oven will expand your options here, and allow you to cook food thoroughly.
Dehydrate fruit and vegetables by putting them in a single layer in the sun. Use the roof or a table covered with a clean cloth. Got a window screen lying around? Put it under the cloth for air circulation. Or use a tray from an electric dehydrator. Cover the food with cheesecloth or netting of some kind - old nylon curtains work well - and set it in the sun. You may have to move it a time or two to keep it in the sun so a small table is easier to handle.
Everybody knows about sun tea, don't they? Just put your tea in water in a glass jar and set it in the sun. Use the same method to make herbal tea. Warm lemons in the sun, then roll on a flat surface and you'll get more lemon juice for lemonade.
Dry your clothes with a solar powered clothes dryer, of course.
And if you do want to put a little money in it, there are many, many small and large products which either operate entirely from solar energy or uses it for a backup. Everything from electric fence chargers to automobiles use solar rechargeable batteries.
Solar power rocks... especially the free kind.
More ideas here: Solar Power for Fun and Savings