The possibilities for getting a phone at a subsidized price (via Verizon, Best Buy, Costco...not Amazon or Wirefly) are...
One option is if you have more than one line on your account, with an upgrade due. If one of those lines are tiered (limited) or is a dummy line (has no data), then you can transfer the upgrade to that tiered/dummy line, buy a phone at the subsidized price, then activate it on the tiered/dummy line. If it's a tiered line, it will remain tiered and that line's contract will be updated. If it's a dummy line, then you will have to choose a tiered package for that line. Once the new phone has been activated on the tiered or dummy line and that contract updated, you can switch the phone over to your unlimited line and keep unlimited. If it was a dummy line, after you move the new phone off that line and put the dummy phone back on that line, you can cancel the data package. BUT you have to make sure you activate the new phone on the tiered/dummy line first before you move it to the unlimited line.
Another option is if you have more than one line, both are unlimited but you don't mind that one of the lines becomes tiered (maybe that person hardly uses data at all). You can transfer the upgrade to that line, activate the new subsidized phone on that line, choose a tiered data package for that line, then once that is all done, you can move the new phone to the other line and keep unlimited on that line.
The last option (but the worst one) is to add a line, buy the new phone on that line, activate the new phone on the new line, choose a tiered package for that line and once that is all done, you can move the new phone to your unlimited line, put a dummy phone on the new line and cancel the data package on the new line (but you would still have a $10 monthly fee for that new line for two years...costing $240 for a line you may not need).