Is there a discount for 4 lines? Like Google said 4 lines for $30 each line.
Assuming you aren't already getting some other type of discount like a job-related one or are already under contract with your other Verizon lines where there is some kind of promotional discount tied with those lines, then yes, you get a slightly better multi-line discount for 4 postpaid lines under one account as compared to 2 or 3. If you're prepaid, there's a multi-line discount for having several prepaid lines under one account, but I'm not sure on the exact details for prepaid. The website will have more information.