I have a 2 line family plan both with unlimited data. Both are eligible for an upgrade soon. I don't have a dumb phone but presumably, I could buy one off of craigs list if I need to.
I want to keep unlimited data on both of my lines so to get a subsidized phone, I would need to add a line, yes? Then I could get a new smartphone on that line but switch the smartphone to one of the unlimited data lines and put the dumb phone on the new line. Then I could transfer the upgrades from my unlimited lines to the new line twice and get 2 more new phones at the subsidized price each time switching back the new line to the dumb phone?
Yup, from what I was told by the rep, and what we wound up doing, this is the case.
You need to have a dummy line, or at least an active line on your family plan that doesn't already have unlimited data to use as the middleman.
But the gist is to just transfer all the upgrades to that line, do the upgrades, then move the phone over to the original lines. As my case proved, the system doesn't seem to care that my mom's line was changing between like 3 phones within the span of an hour.