Dell often holds sales on its computer hardware and accessories, you just have to keep your eyes open until the gadget you want is discounted. If you don't mind refurbished gear, you can possibly get what you want even cheaper by regularly pointing your browser to Dell's Outlet site.
The Outlet site is pretty plain but easily navigated. Categories range from the typical (notebooks, monitors and desktops) to the specific (storage and servers) and covers pretty much anything you might want to pick up from the retailer. Clicking on a category will present a list of available components, with brief details and pricing. To order something, you'll need to call the provided number and quote the bundle reference (the leftmost column on the product listing).
A good category to keep an eye on is Monitors, especially if you're keen to pick up one of Dell's excellent UltraSharp models. Take the popular 24" U2412M display -- it usually retails at $399, sometimes going on-sale for $279. Refurbished, it's been listed for as low as $210 and that includes a one-year limited warranty.
On a related note, Dell is currently holding its end-of-financial-year sale. Laptops seem to be the focus now, but you can hit up other parts of the site for more deals. For example, until June 20, you can get a 29" U2913WM display for $419, down from $599. Now, a 2560 x 1080 screen might sound excessive for some, but I know I could make good use of that desktop real estate.