iPhone Forever

Hi,

I currently have an Iphone7 and I would like to upgrade it. My friend told me about iPhone forever and I would like to know the details it, such as: (1) how much would my first payment be? (2) how much would I pay monthly for an iPhone XS max? (3) when will I be able to upgrade, (4) How much will I have to pay when I decide to upgrade.

Best,

-Leana