Do I really need an iPhone at this point?

I've never had a smartphone before and, with my limited (current) needs and usage, I'm not sure I need one.

I DON'T 1) Download music
2) Download movies
3) Watch streaming videos
4) Watch streaming TV
5) Surf the web (old eyes - better done on a large screen iMac)

I have an old (read antique - at least 5 year old plain dumb cell phone) that i use for just that - cell phone calls and limited texting.

With the new plans offered by several carriers (I currently have Verizon) and several, what appear to be, attractive purchase/limited usage plans offered, is it time to buy a 5s or 5c just as a move into new technology?

With my limited current needs, what size of a data package should I look at? Verizon's 45 Plans start off with 250MB data @ $45 then goes to 1GB @ $60 and works upward from there.

I guess what I'm trying to say is how big a MINIMUM data package should I be looking at?

Just to run a few basic apps that I might like to have (weather etc.) what can I expect my monthly data usage to be?

Any guidance would be appreciated.