Well, let's see......
Our discount is cost + 5%. On audio and video stuff, the discounts are pretty good because the markup is substantial. Computer stuff on the other hand is not marked up much at all. In general, accessories like cables, cases, etc. are marked up like mad (in some cases like 500%).
If you get hired as a part time employee, your discount doesn't take effect until you've worked there for the company for over 90 days. If you are hired during seasonal (Thanksgiving/Christmas) your discount starts taking effect after Thanksgiving Day.
There's a big trade-off for these cool discounts though. The pay isn't great. You start at like $6.50/hour and you don't work on commission. I can be making more as a PC tech, but the advantage with Best Buy is that it's close to where I live (less driving).