Send someone a real letter

I sent a letter to my grandma.
She lives in Italy, and I live in London. Calling cost unfortunately too much for both of us, and she doesn't know how to use internet. So one day I decided to send her a letter, as a way to keep in touch with her directly (and not through my dad) and let her know that I actually think about her.
She was so happy. It was a surprised for her, and I was so happy when I heard how much she loved it. She replied, and I think this can be only the beginning of a long series of letters.