iPhone 15 Pro is $49.91 which is $676 with tax
iPhone 15 is $39.50 which is $535 with tax from what I remember
Is it worth it and can you use an Apple gift card $300 to pay the monthly for the iPhone 15 under the upgrade program?
If you go with Apple Upgrade program, you will save $1.69 per month on equal value - which translate to $20.28 every year.
Assuming, for ease of calculation, that prices remain constant (say $1200 for iPhone 15 Pro Max) for every model from now to iPhone 19 Pro Max and assuming that all transactions are within Apple environment, you will save about $680 by sticking to the Upgrade option for 5 years and upgrading your iPhone
EVERY year. This is possible because you are paying only about $580 every year (which means you get a $620 trade-in value on your iPhone compared to $450 if you trade-in outside of the upgrade program - so, $170 per upgrade x 4 years = $680 savings). Of course, you can try your luck in eBay but you must sell at least $700 to make it worth your while, accounting for eBay fees. Pay the Apple Care + for $10 a month, which makes ups the ante to $820 as a sale price. Add the $40 dollar savings you get with the Upgrade program, that pushes it to $860. A used $1099 iPhone 14 Pro Max 256 GB in excellent condition was sold today in eBay at $700, while a used 15 Pro max 256 GB sold at $950. So, the question becomes, do you want to go through the hassle of eBay for $90 bucks.
If you upgrade every two years, the upgrade value has no added benefit as you have paid off your phone. Trade-in value for that phone is only $450 with Apple, but you will have to sell it on eBay at $700 to make it worth your while. ($450 + $50 eBay fees + $199 Apple Care+ for 2 years) (or $750 if you were on the upgrade plan).
This is doing an apple-to-apple (pun intended) comparison on the upgrade program which would make you have an Apple care+ for $9.99 per month. I have taken this out and assumed you take this subscription outside the upgrade program. Of course, you can chose not to do it, ensure your phone is in excellent condition and reduce the sale point price in eBay by $140 after every year or $240 every two years.
Route your Upgrade program payments through a cash benefit credit card and you can get about $12 back every year, or buy your new phone with an Apple Card with 0% interest for 2 years and you can get about $36 back every two years.
Bottom line: if you want a new iPhone every year, go with the Upgrade plan. If not, just purchase it on your Apple Card (to get the 3% cash back) and pay in 24 months. Remember, with the upgrade plan, you cannot switch to a non-apple device. You are locked in to them for 2 years at least.