I went to google and typed in "source code" and the name of the store. Click, click, click. Done. It was well worth my time. If you look at it in terms of an hourly wage, I would be saving / making about $1800 an hour! (Dream on.)
When making your online purchase, near the end of checkout, usually you'll find a little square box asking you if you have a promotion code (also known as a source code or coupon). Now's the time to have a magic phrase. Open a secondary window. Do your search. Enter the code and voila! instant discount.I have a few direct links for you to bookmark: here, here and here.