Mileage on a 2006 F-150?

There is absolutely no way to know that. It could last another 20 years and a million miles if it has been and continues to be properly maintained. It could last 2 months or it could blow up as you are driving away with it. There are no expiration or use by dates on cars and trucks. It depends on how well you take care of it, how well the previous owners took care of it, and on and on. Being four years old with 130K on it already, that truck has over twice the average miles for a 2006. Make sure a mechanic checks it out before you purchase it.