Least expensive way to make your own solar oven can be viewed at this link. Have fun cooking with your solar oven and saving money at the same time.
There are many styles of solar oven cookers that can be used to cook with. Each one will reach different temperatures that you need to take into considerations, when you choose which style will be best suited for your family.
Here you will learn about the different types of solar ovens. I use the solar box oven type pictured above, it will reach temperatures up to 400 degrees. Here is a link that will explain the different type of solar cookers that are available and the advantages and disadvantages of each type. http://en.wikipedia.org/wiki/Solar_cooker
The most common and affordable way to make your own is to simply purchase a sun visor reflector, 5 gallon bucket, and round rack to place your dark cookware onto and oven bags. Place the sun visor into bucket with a few small bricks in the bottom, to secure it from tipping over. Then place the rack in the center, then place your cookware with your food inside the oven bag.
This link will give you an idea of the different styles available that you can make from the free plans available. http://www.solarcookingatlas.com/make-sun-oven-solar-cooker.php
You should have a temperature gauge placed in your food, to insure the food is at a safe temperature to avoid food poison. Food temperature needs to always be above 150 degree’s to avoid getting sick from bacteria growth in your food.