International call to and from USA

sparkeytec

Hi all,

i was wondering if anyone could help with the confusing situation of calling and receiving calls from the USA.
My girlfriend is in the USA for a few months. She has her UK mobile with her but i am going to get her a T-Mobile US sim to cut down costs.
I am going to get it from this site - icallabroad.com


unless anyone has any better alternatives??

Now i will be calling and receiving calls to and from her using this sim to my vodafone mobile so no landline calls will be made, just mobiles only. I don't have regular internet access so Skype isn't an option.
Now my questions are:
1. If she calls me from her US T-mobile using an international calling card will i be charging for reciving this call on my vodafone mobile?
2. If i call her from my mobile using an international calling card will she be charged for receiving the call. If so does anyone have any idea how much?
3. If shes call me from a landline in the US using a international calling card to my uk mobile do i incur any costs for receiving the call?
4. Is there any other costs that i should take into account

Many thanks in advance for any replies