I worked at Circuit City, and we saw the profit margin on every item we sold (and were required to maintain a certain margin percentage in our sales). I worked in the audio/video department. The margins people are quoting are way too high. For stereos, dvd players, tvs, etc, margins ranged from negative to 25% on average. The higher end items had a greater margin. The cheaper items had hardly any margin at all. Speakers had the highest margin, and were as high as 50% on the high end ones, but sales on cheap speakers were often below cost. Accessories have like a 75% markup.
Our sales screen showed margin in 2 digits. For negative margins, it would show -5 or -8. For negative margins greater than 9%, showed **, as there are only 2 digits available. So we were NEVER to sell "double asterix" items. That could be anything from -10% or higher, and could kill your margin for the day.
I remember this one time, we had some cheap Pioneer speakers on sale for $29.99 each. They were ** margin. Some guy asked what price I would give him if he paid cash. I said, "$29.99". Like I care how he pays, and like I have the ability to change the price. Do you go to the grocery store and ask what the best price they'll offer on a gallon of milk?