Unlocked phone with at&t service

I am currently on at&t customer, and plan to buy an iphone and unlock it in order to use my current rate plan (without data plan).

I have research about wifi on unlocked phone, and it seems to look
if I have at&t service, the edge would have priority over wi-fi.

My question is that

even though I am not having any data plan, I would be charged for using internet in wifi available area because of Edge priority?

I will always use wif for internet and never want to use EDGE. If i have an at&t service, do I have to install deedge application?

Thank you

Wifi defaults over edge. To be on the safe side I'd use deedge to save on the data charges b/c I've slipped and loaded safari without having a wifi connection, and 10 cents a k/b adds up quick. Hope that helps.