I was able to go by
Walmart this morning after work and I picked up a cooler, and a few other things. The cooler cost $5.77 plus tax.
I also bought a document holder. It is made out of thin plexiglass. I als picked up a tube of Dap Kwik Seal (kitchen and bath adhesive seal-clear) I used the cardboard top off of the document holder to act as a straight edge. I simply scored the plexiglass with my razor knife. I started out with light pressure and gradually added pressure with each pass. After about 10 or so passes you can simply snap it off like sheet rock.
Next I took a sheet of copy paper and folded it. I made a fold about 1/2 inch all the way around. You can see the paper on top of the plexiglass. This will be your template to cut the hole for the window. Since the document holder had two pieces of plexiglass after it was cut we can have a window on the top and the side.
Here is the paper pattern.
Here is where I traced around the paper.
I cut the hole out with a razor blade. Be safe, I lost my holder so I used a blade by its self. But this should give you an idea of what I used.
Next I ran a bead of silicone around the top, all the way around.
And here is the top all completed.
If you want a window in the side just do it exactly like you did the top.
Pattern.
Cut out.
Window installed.
The finished product.
Here is the two pieces that was cut out.
The cooler was $5.77, document was around $3.00.