I checked the local MicroCenter and didn't see any refurb/recertified laptops in the price range you wanted.
I also checked TigerDirect and the only under $300 models I thought were worth looking at were "off lease". A Dell Latitude D630 C2D @ $290
and Lenovo ThinkPad R61 @ $300
Off lease is a lower-grade option below refurb/recertified and usually have a 90 day warranty. I can't recommend something like that.
Especially when you get a decent new laptop with warranty for @ $350.
If you want to keep checking on good deals I like to use Dealigg
You probably want to avoid the 'Netbooks and also the Notebooks with Netbook CPUs (AMD E-350 or Intel Celeron 900 for example)