The iPhone price signs in-store are a point of constant confusion because they only show very specific payment methods, options and options for each model.
I would propose adding the one-time payment options to all models and adding a field for whether the phone is available unlocked (yes or no).
Additionally, when I was looking at printers, I noticed there's a banner at the bottom now that says if the item is in stock or not. This banner could be useful to add to the iPhone signs to callout that additional storage capacities and payment options (i.e. the 30 month device payments on Verizon) can be accessed by scanning the QR code.
As it stands now, it appears (based on the signs) that Best Buy may have only the lower-capacity storage offerings for all devices and/or may offer different payment options for Verizon customers than what may be had at the carrier so implementing these changes (and especially the unlocked) could help signficantly.
I would also recommend changing the verbiage to be uniform across all models - "Upgrade" or "New Line" following each option on the price sign, so for instance (final product):
Monthly Installment - Upgrade
Monthly Installment - "New Line" (this is currently just Monthly Installment)
One Time Payment - Upgrade (this is currently flipped with New - keeping the upgrade/new pattern would help minimize confusion more).
One Time Payment - "New Line"
Available Unlocked: Yes / No (whichever the correct response is).
Banner at bottom: Additional storage and device payment options may be accessed by scanning the QR code.