Since it's a dated card and you can get a x1950xt relatively cheap, I'd say maybe $100 - $125 if you wanted to get rid of it asap. You might be able to talk someone into $150
I agree with this more or less. You need to realize that the warranty does not transfer over to the new owner. Therefore, whoever is buying the card receives it "as is", if the card fails the next week then kiss your $$$ goodbye.
Actually, I wouldn't pay $150 for a card with no warranty.