Depends on the flexibility you want. I’d say carrier financing is going to be a poor option when done directly through T-Mobile. Your phone will be network locked, making switching carriers later more difficult; however, you get promo pricing on top of trade-in. That said, T-Mobile EIP when done through Apple.com is slightly better because you should be receiving an unlocked phone and you still get the promo pricing. But, you’re tied to your carrier and lose promo bill credits if you pay off the phone early to switch carriers. If you don’t mind missing out on promos and only taking a trade-in value credit, there is also the option of 0% financing directly through Apple (Apple Card, iPhone Upgrade Program). Personally, I find one-time payment the worst option. Unless you’d consider yourself poor with money management and need to spend cash as soon as it comes in, all of the financing options are 0% with $0 fees.
