Buy Iphone without using it as a phone?

So I wanna buy a refurbished iphone from gamestop and I was just wondering… If I just wanted to use the phone for now without actually activating it and using it as a phone, could I still use it? Or would i have to activate it first?

Added (1). I will be using the phone as a phone and activating it later

Could always just get an ipod touch instead, but ya you can use the phone without service but you might as well get an ipod touch

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