Compare family mobile plans on total cost.
Family mobile plans are advertised at a per-line rate that already assumes the multi-line discount, and then two things are added that the advertisement omits. Device instalments are a separate loan — you are financing a handset, and it appears on the same bill without appearing in the plan price. Taxes and regulatory fees then apply to the whole thing and commonly add 10 to 15%. The all-in cost per line is therefore substantially above the headline. Two things to check: whether the discount applies to every line or only from the second onward, and whether it is a promotional rate that steps up after twelve months.
Family Text Plan Cost
List = lines x per-line cost; service = list x (1 - discount%); monthly total = (service + device instalments) x (1 + taxes and fees%)
Almost always device instalments plus taxes and regulatory fees. Together they routinely add 20-30% to the plan figure, and neither appears in the marketing price.
Yes, substantially — a four-line plan is typically 30-50% cheaper per line than four individual plans, because the discount grows with the number of lines.