How low can notebook prices drop?

What can you get in an entry-level notebook (not netbook!) these days? Best Buy and Wal-Mart have had $300 laptops in the news lately, though it appears both are "limited quantities/availability". Rather than restrict ourselves to short-term sales, we wanted to look at the specs of a few sub-$500 notebooks you can currently buy. We'll start with Wal-Mart's $300 offering as the baseline - it went on sale this past Sunday Morning (July 26) and likely sold out shortly thereafter. However, it's an in-store-only offering, so unless you run by your local Wal-Mart(s) there's no way to know for sure if it's available or not..