It really depends on the state. I think Delaware is all paid, but Pennsylvania is mostly volunteer with only a few cities having full time staff like Philly, Chester, Harrisburg, etc.

But like even west Philly in the Drexel Hill area there’s a big volunteer company. West Chester does have a fully staffed volunteer ambulance company called Good Fellowship.

You’d have to look into your local to see. Also lots of volunteer places will let you join even if you are far away as long as you get enough credits each year (say by coming and working from the station and going on calls during the day or going to weekly trainings).