How much different is it to set up & activate a USED iPhone than a new one?

I'm planning on buying a USED iPhone off ebay, and I've seen the videos for how to activate %26amp; set up a NEW iPhone, but how much different is a used one to set up %26amp; activate with iTunes, compared to setting up a new iPhone? Any help would be great. Thanks!How much different is it to set up %26amp; activate a USED iPhone than a new one?Are you try to use in att and willing to pay 20+ bucks data/msg plan in that case then go use the itune, but you should check if the ebay one is unlocked, with unlocked is easy just insery you current sim card, but if you need a new plan go with tmobile because they had 5 dollar data plan compare to att 20 bucks.