How does the iPhone bill work exactly?

My family has the family plan on verizon wireless and I was wondering what would happen if I were to replace my flip phone with an iphone 5c. How much would the price go up? Would it just be the $30 (or so) for the data or does the iphone make you pay a ton more just for it being an iphone?

Hi, fellow Verizon customer here, been with them for a decade.
No, if you are on a family plan, you have to pay for being an additional line in that family plan, these additional lines cost differs between basic and smartphone, so obviously your family was already paying an additional line cost because you have a basis.phone. But you'll have to pay 10~20 dollars more if you want to upgrade to a smartphone, or more specifically an iPhone. Other than that, there's no other hidden fees, if you want messaging, you have to buy messaging, but no one really does because Wi-Fi is everywhere nowadays, and 4G coverage is HUGE for Verizon, there are apps so you can text your friends.

Other than additional perks, the only "hidden" cost will be the additional line cost that will go up, you'll likely pay 50 dollars for your phone bill if you buy the lowest data package, and including the twenty dollar smartphone line fee. Have fun!