So, a while back, being the Ecogeek that I am, I found this on www.ecogeek.org: http://www.ecogeek.org/content/view/2679/
...Which is pretty awesome, because people in less privileged areas would be able to use this, as mentioned in that article. So, my friend and I decided to give this a shot...and where else better to do it than on instructables!
The only part that really cost anything for us was the glass, because we didn't have it on hand. This was bought at Home Depot and a sheet of 12"x36" was bought, which cost a grand total of $10. We only used half, so it technically only costs $5.
All the other materials are from around the office and around the house, which cost us nothing, as it was really just trash.
It's great for cooking cookies, among other things. As you will see, the glass and extra weight provides added pressure, plus the heat which aides in the cooking of the food. As always, we recommend using a food thermometer before you eat the food to ensure the proper temperature of the food that you eat to prevent food poisoning.
**Disclaimer: We do not assume any responsibility for the quality of the food nor the quality of how cooked it is. By using this cooker, you assume that all food is safe to eat and do not hold the author of this Instructable, his affiliates, Instructables.com & their affiliates responsible for any of your misactions.