I'll tell you how. I went in to buy some button batteries for my keychain flashlight. I needed 4, salesman said it would cost $20 bucks. I felt it was too expensive but bought it anyway, thinking they were a specialty item. That night I go on eBay and found out I could have had 4 for $5. They sell basic crap and stuff for big margin. You open their flyers and see a huge ad for a alarm clock at $25. The only way they can justify the full glossy ad for stuff like that, is because the margins must be killer.
Couldn't said it better myself. When I visit my Mom at her vacation cabin ( small town ) Radio Shack is it, Wallmart is 60 minutes away. 1 CD-R for backing up data $1.75 plus tax! If they are smart they will stay and small towns and focus on service and speciality items, otherwise they are done. Their service is good compared to Best Buy, Circuit City, etc, but $$$.