WTB: Cheapest Laptop w/ GOOD battery

[Fightguard]

Helping out a friend here buying a laptop...no set budget right now but the idea is to pay the lowest price possible for a laptop with a GOOD battery. only other requirements is that it has a CD-ROM drive and can run 2K/XP okay.
Ideally, a lower-end ~500-600Mhz would suffice (w/ win2K) but we realize used ones that are realtively older usually have batteries that don't hold a charge for very long.
although we can probably buy and older laptop and try to find a replacement battery for it, let's see what kind of offers we can get here first
Thanks.