It's like AviatorTJ said, Apple keeps the prices controlled so there's very little variation. One thing you can look for is bundling offers. From time to time, you can get a "free" scanner, printer, digital camera, memory upgrade, or something similar. Especially if you'd need to buy any of that anyway, you can think of that as a bit of a discount.
The education discount is about the only discount, if you can qualify it. It doesn't have to be higher ed all the time; my mother got the discount and she's a kindergarten teacher. You can get the discount on hardware both on Apple's web site and in a retail Apple Store.
Finally, if you don't mind slightly older, or used/refurbished equipment, look for the red Save tag on the front page of the Apple Store web site, which will take you to a page with older and refurbished hardware that is discounted a bit. You can also try Small Dog Electronics
, which sells a lot of used Apple hardware. I got my iBook from them. Finally, there's always eBay, but be careful there, a lot of the listings really aren't much of a deal.
David / ABQ