WHAT IS the most months u can finance on a mercedes??

The longest I've seen at a bank is 84 months but different banks and financing institutions will have different loan periods.

Just keep in mind that while longer financing periods offer you lower monthly payments, the interest/financing charges will really build-up over the years. In my thought, if this is the only way you can afford a new Benz, you would be better off looking at either a less pricey automobile or if you really want a Mercedes, look at used models.