Plan(s) suggestion

At the moment I have all 4 lines sharing a pool and it generally uses 8 gb/month. It's a great deal and I'm very happy with the verizon service for my area. As someone who can't work because of the meds for my cancer I'm always looking to save money. There's myself, wifey and 2 just passed teenagers. I wonder if anyone has any suggestions. I can't afford the initial cost of annual plans or I would go that route.We use wifi calling primarily and are mostly able to access wifi. Any suggestions are welcome Thanking You in advance.