What is the best cell phone and plan for coast to coast travel?

I need a cell phone that is always available. I have never owned a cell before and don't know what to look for.

I need a phone that works coast to coast north to south, no matter where I am in the country I need to be able to pick up that cell phone and be able to communicate with customers and dispatch and they need to be able to contact me.

at&t has the best nationwide coverage.

I have thought of the Rumor LG being the best phone from Sprint. It is 39.98 for the phone and the plan is 450 min. and unlimiting txt. for 49.99 a month, but if you want 900 min. and unlimited txt. it is 69.99 a month for the phone, so it's not bad, but still good service.

AT&T is also one of my family's favorites, but I never trusted them, cause the whole bill cost $89.00 to $100.00 and I dont have that kind of money.

Also get a pre-paid phone, those are well usable. :)

at&t has the best world coverage.