Kristy added a comment that they put a box in their church lobby for church people to put cards for each other. The box has slots for every letter of the alphabet so people can send cards to each other without having to worry about postage expense.
Another idea is for people to send one card to everyone in church. Those cards can be hung on a tree or hung somewhere in the lobby. This also allows everyone to read cards from missionaries and far away church members – who send cards to the church. Sometimes not everyone gets to see these cards and read them. This allows everyone opportunity to see what’s happening in those people’s lives.