I've researched it and learned that if she was carrying the AT&T variant, they always come locked but per request from AT&T customer service, without regard to whether the device was subsidized or not, they just hand you the unlock code.
So the question is now, would she use roaming or would she obtain a Turkish prepaid line?
With a limited budget, one would perhaps be inclined towards to skip using roaming, relying on Skype or preferring a prepaid Turkish line/card.
It all depends on AT&T roaming charges. Are they outrageous as it's the case when I go the States my operator charges me an arm and a leg for roaming?