I'm a bit late, too. Two thoughts:
1. Three's Feel at Home program is amazing. Like politicfool, I also just use Google Voice over data to call and text.
2. Before Feel at Home, I used PlatinumTel's PayGo plan (
https://www.ptel.com/plans). It's the cheapest I found per year to maintain a "real" US number ($60/year, topping up $10 every 60 days). The only downside is that they use the T-Mobile network, which isn't always the best in rural areas. I've experienced good customer service, aside from very long waits on the phone to talk to someone.