Along with the birthday theme, I have been able to eliminate spending money on Birthday cards. Now that I have kids, I let them color or draw a picture and write their name on it. Voila! Instant card. I think it also makes the gift giving seem more meaningful to my children - they are involved in the process.
Another benefit from saving money is that so often cards just get thrown away - even if the artwork gets thrown away, at least it isn't like just throwing away money. Of course the grandparents, Aunts and Uncles like to keep the pictures!
So next time you have a gift to deliver or a card to mail, set your child down with some paper and crayons and let them create the perfect card!