Hi Jane and welcome to the forum!
Have a look round. You’d need to check compatibility of the FP model with local providers’ networks, but there are FPs in the States.
See specifications:
FP4, the latest model, seems to have good compatibility with T-Mobile for example:
For second-hand phones, also look round and keep coming back (click the “Offer” category), there are often people offering to sell, see this: