Iphone 15 payment

I’m looking to buy the new iPhone 15 by November but I’m an AuPair, so I don’t really want to pay it completely with cash bc it’s a BIG amount of money, but the installments are for 24 or 36 months, I’m just here for a year, could extend for another year but still, I’d rather pay like half of the total price right away and the other half in installments and according to how much I can spend each month maybe do bigger payments so that I can finish paying for it even sooner, but idk if I can actually do it. I know I can buy it from other stores but at least with Walmart it was the same deal, what would you recommend?