Facebook messenger and facetime data

[JABB]

If I wanted to contact by voice someone in the US for free, and I initiated the call, would the recipient get data charges if unable to use wifi, and only use 3G?
FB messenger says data allowance is used, but do both parties get the hit?

[JABB]

OK, but will it just show as data, and how much data would a facebook voice only app use per min to and from the US?

[JABB]

Thank you