Someone is trying to scam me right now please help!?

You can contact your local authorities who will either give you a number or put you through to a department dealing with online fraud (although this probably won't be local) where you can leave the relevant information about the seller. They may request copies of all mail sent and received, and will take it from there. There's nothing you can really do to help unless instructed to by the authorities, but this is highly unlikely. P on his details and p up on his 'deal'.