ah didn't really spend all that much time learning how to navigate new egg, but the cheaper the better (don't quote me)
if your client is going to be using very simple applications then a mere stick of 256mb and a cheap cheap (i mean 2 years ago I saw semprons for £27 retail new, and that was 2 years ago). If by simple apps you mean programs like office etc, then the computing you need will be relatively very affordable and much below your $250 budget