A small relative is having his first birthday soon, and his mother wanted to buy invitations to send out for the party. Since the little guy is currently obsessed with Thomas the Train (Thomas & Friends), I started searching the internet to see if we could make the invites cheaper, and I found that many PBS cartoon characters have free "print-your-own" birthday party stuff. (There are generic party themes, too, like "science.")
Here's the index of available themes:
http://www.pbs.org/parents/birthday-parties