Q: adding a used ipone to an existing itunes account

Hey rytamsyd,

Thanks for the question. You shouldn’t have any problem using the device as if it were an iPod touch. However, here are a few things to keep in mind:

Before transferring ownership to you, the previous owner needs to sign out of their iCloud account to turn off activation lock:

iCloud: Find My iPhone Activation Lock in iOS 7

http://support.apple.com/kb/HT5818

To use an iPhone without a wireless service plan you need to activate it first, then remove the sim card. If you wish to update or restore the device in the future, it may be necessary to activate it each time:

Using an iPhone without a wireless service plan

http://support.apple.com/kb/HT3406

The previous owner may wish to look over these two resources:

What to do before selling or giving away your iPhone, iPad, or iPod touch

http://support.apple.com/kb/HT5661

iPhone: About unlocking

http://support.apple.com/kb/HT5014

Thanks,

Matt M.