First for a long time Verizon had the best coverage. I'm not sure that is still true.
There are a lot of "pre-paid" plans.. YOu can get a phone with a limited number of minutes at gas stations. Truck stops. Drug stores and more. Depending on the phone it will most likely work with T-Mobile. Sprint or the most popular is Verizon. (Virgin Mobile uses Sprint)
These plans, depending on how much talk time and data you want, can be as low as 20-25/month (I used to use a Virgin Mobile data plan,, it worked where I needed it,, So I'd go into the store and ask for a "Twenty Dollar Virgin".. Got a laugh most times since the clerk knew exactly what I wanted)
IF you are not planing on being in the USA too long.. That's what I'd recommend.
Long stay you might want to look at other plans.
Side note.. Went to Marysville, MI yestarday.. Got a "Welcome to Canada" message on my T-Mobile.... I Never left Michigan.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times