re: Questions re: "in and out" vehicle purchase

In Louisiana the seller gets tax credit for his trade by doing an in and out. If he sold you his car directly to you he wouldn't get credit for it. He would pay tax on the full price of his 'new' car vs only paying tax on the difference between the 'new' car sales price and the trade amount. This only works if he is trading in a car and buying another. The dealer benefits bc they get the sale of the 'new' car and also immediately get rid of the traded in unit, which they might have sent to auction and take a loss on.