Mark, if you already know that you don't need many minutes (if you have an average usage number), it won't be that difficult for you. Pick up a good, cheap, carrier unlocked $20-35 GSM feature phone (from say Nokia, LG or Samsung), and shop around and compare PAYGO and package prices between PureTalk USA, Airvoice or P'tel. So long as you get good AT&T or T-Mobile reception, you're golden.
If you find you need CDMA/Verizon coverage instead, look into digging up a good shape, used, non-LTE Verizon flip phone that you can activate on an annual PAYGO plan with either Page Plus or Selectel.
If you want to go Sprint, go Ecomobile. Ting is only a good deal for multiple lines.
If your normal usage patters will never spend more than $10/month anyway, you can get a cheaper feature phone and no Republic plan will ever save you money in the long run. Just pay for what you need, and don't worry about trying to do the more technical usage hacks.