We've switched Chef Elaine's iPhone from Verizon to Total by Verizon. Same Verizon network but for less than half the price, with her monthly bill averaging $65.20 reduced to $31.19 and the amount of data increased from 2 GB to 5 GB. That's a yearly savings of over $400.
We just bought a Total by Verizon SIM card (picture below) for $0.99 at Kroger and followed the setup instructions. She'll still get unlimited talk & text, including Canada (good) and Mexico (don't care).
Most, but not all, cell phones can run on Verizon's CDMA network and locked phones can be an issue. Check out your phone at the "keep your own phone" link below.
Big shout out to my buddy Nick for this huge money-saver!