So I'm looking to buy a pc from this guy named Clayton. His website is http://www.valkyrie-pc.com/ now I'm going to meet him in person tomorrow, and he told me he didn't want to buy any parts without some down payment so he doesn't lose money if i op'td out. Now so I know I won't lose money or get scammed, what paperwork would I need him to sign, etc. so if god forbids he just doesn't build my pc I can sue him and get all my money back? Thanks for response in advance!