I haven't really played D&D in years. But I'm planning to get the new rule set to read about the changes. I understand it's moving towards a more computer-assisted playstyle, or some such.
Right now, if you have a Barnes-and-Nobel membership, you can get the three-book core set of 4th edition rules for $60, including shipping/tax.
Regular price is $105 (for the three books) + tax. Currently on sale for 30% off (online only), then members get 10% off, and members just received an e-mail coupon for another 15% off. Free three-day shipping. Total (including tax) is just under $60.
clicky for B&N