Depends
I paid more than that for my refurbished Intel core duo Macbook with only 1 GB Ram.
But keep the seller in mind too. Do you know them? Are they reliable? Is there anything wrong with it? Is it legal? (you don't want to find out it was stolen)
I'm sure there can be good and legitimate reasons for a great deal and low price, I'm just saying be careful. You don't want to plunk down your cash, have the machine croak two days later and find the seller skipped town and you have no mac and no money.