Nothing out of the ordinary:
Tracfone promo codes will get you free minutes on top of purchased minutes (this is a very expensive route for compulsive yakkers). I used to get away with about $20 every three months, but I'm not nearly as chatty when on the phone. The least expensive card is $20 and is good for so many minutes, it will expire in three months whether you use it or not.
I have googled "prepaid hacks", "tracfone cheats", "prepaid phone cheats"and more and have come up with very little useful info. I'm under the the impression that they have a pretty good grip on avoiding giving away service.
I did find how to receive free inbound texts on a certain Tracfone model (if it has service already).