What are your preferences regarding phone models? With low data usage you could look at carriers like Mint (runs on T-Mobile, pre-pay for the best per-month rate), Ting (Sprint I believe, may have options for different carriers), or even Google Fi.
Google Fi will be restricted as to what devices you use, in order to get the full feature set. I'm on Google Fi and been happy with it for the most part including traveling internationally (Mexico and Canada last year). Fi runs on T-Mobile (primary), Sprint and US Cellular towers. If you decide on Fi, I can get you a code that gives you $20 off your bill (and me $20 off my bill) after you've been with the service long enough for the second bill to generate, but we would know each other's real names.