walk across the country

I need to finish Highschool before I do this and I need to figure out how much money I’d need. Food isn’t free afterall. I can sleep in a tent but the occasional motel room would be nice.
A list of necessary supplies would have to include:
A very good pair of walking shoes
Clothes (need to find out what kind of clothes, light, heavy, etc)
Backpack
camelback watersupply

That’s just the absolute mandatory. I’ll have to think a little more on it.