Search Google Shopping by UPC Product Code

I have recently found an awesome way to do comparison shopping online with the Google Shopping Search Engine. Instead of doing simple keyword searching you can visit your local store that contains the item you desire and write down the UPC Product code. This number is usually either 8 or 12 numbers long. This includes not only the numbers in large font but the smaller numbers to the left and right of the main UPC code. Once you have the code enter it into the Google Shopping Engine Search Area and enjoy your finds.