Right now, when you buy an Apple Gift Card online at Target, you can get a $10 Target Gift Card back with a $100 purchase. After Apple’s gift card revamp, the Apple Gift Card can be used across the Apple Store, physical retail stores, and iTunes, and it can also be used online or in store to buy the new iPhone 13. If you were already planning to buy one, this works out to about a 9% discount.
If you have a Target RedCard, you can probably also get 5% off when buying the gift card, which means close to 15% off an iPhone.
Of course, paying with gift cards will likely cause you to lose your credit card’s purchase protection. I’d suggest paying for most of it with gift cards, then using an AMEX card or another card with purchase protection for the remaining balance. You might still be able to keep the purchase protection that way.