Beckee says:

One of the cheapest and most efficient ways to harness solar energy is to dry your clothes on the line. You don’t need to convert it to electricity, and you don’t have to heat up your house with an electric dryer and cool it off with fans or air conditioning.

That reminds me, time to get my clothes off the solar clothes dryer!

cdf-rom says:

The cheapest PRACTICAL way of using solar energy at home is to make a solar cooker.

This is not a solar ‘oven’ with a big lens or mirror that broils things, it is a box painted black that gets hot as it sits out in the sun the same way your car does. They only cost a few bucks to make and they WORK! I made one and it works!

You will need two cardboard boxes that fit inside each other, some black paint, aluminum foil, glue or tape and a plastic oven- roasting bag like for a Thanksgiving turkey.

It is a slow cooker. You can’t burn anything in it, because it only gets up to about 320 degrees F. in it. The beauty of it is that it saves you energy (and money) two ways: first, you don’t need to run your stove on a sunny day to cook. Second, you don’t need to run your air conditioning extra because you didn’t heat up the house with the stove on!

Search on solar cookers. You will find sites with plans and step by step directions. Have fun!

PS. Beckee, I have to admit, your idea is the cheapest and the easiest. I forgot!