That isn't enough information to provide you with a suggestion. What kind of devices will be on the three lines? How much data do you need? Do you need a mobile hotspot feature?
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
What’s the current most efficient plan for three lines?
There is no such thing. The most efficient plan for 1 family with 3 lines may not be the most efficient plan for another family with 3 lines, or do you actually think what someone else thinks is best for them would be the best for you? If that is the case, definitely get the Play More Unlimited plan with 3 lines as THAT is the most efficient plan for my family.
It's important that we gather additional details in order to help you find the best plan. As other community members have mentioned, there are many factors when it comes to selecting the best plan. How do you intend to use data service? Tell us more about the other lines you plan to add to the account. Here is a link with our current Unlimited plans:https://www.verizonwireless.com/plans/unlimited/.