Have you ever wanted a portable food warmer but didn't want to spend big bucks?
This lunch box using the concept of the green house effect. It can warm most food up in less than an hour and it costs less than $10.
Step 1: Materials
I purchased all of these items at Wallmart;
A lunch box with a collapsible top compartment: >$5
A space blanket: $1
A square foot of clear plastic: $1