I might get excited over a 50% off sale at CompUSA, but I'm not so sure that 10% is worth even going to the store...
In my area, at least, CompUSA charges more than list price. For example, if a video card lists at $149.99 at the manufacturer's web site, then CompUSA will sell it for $150.00 + tax, or even $160 + tax.
The only time I go to CompUSA is when they advertise free stuff, and they usually screw me over in the rebates. Oh well. One day I'll learn my lesson and stop trying to get them to honor their rebates.