306 will definitely be long distance from Calgary. It's a Saskatchewan number. Doesn't matter if your friend is standing next to you, 306 is Saskatchewan. Anyone calling her from the area will be calling long distance because the home area for her phone is Kindersley in this case. If she called you from her phone it would be a local call for her because outbound local calling is based on the tower her cell is connected to.
But your friend is getting a great deal by using a Saskatchewan phone plan while living outside Saskatchewan - even though it costs you a bundle to call her.