There is no way in hell I would buy from someone with zero feedback.
For me to buy they have to have atleast 25 positive feedbacks.
Your sending them $150 of your hard earned money to a zero feedback Ebayer.
Also remember the saying if it sounds to good to be true it is, applies here, why would he sell a $300 item for $150, unless he just wanted to scam someone for what he could.
Take my advice dont do it.