2000 coast to coast, but all the states you cant drive to hawaii, so i would say at least 6000, also a lot cheaper if your good without a hotel, you can sleep in rest areas, buy a small stove and instead of restaurants by soap cans etc.seriously just have fun, money is also possible in towns where you can quick carpentry, or painting, house sitting jobs etc.
Your question is confusing.You can t visit all 50 states by car.Hawaii is a big problem.You re looking at thousands of dollars if you want to drive through all mainland states. I suggest you look at a map. It s going to take weeks( months ? ) to do.