At the beginning of each school year I like to take a picture of my class holding letter signs that spell thank you. I print them out (2 or 3 on a page) from a colored printer. Next, I glue the picture onto a half sheet of construction paper (or colored card stock) and fold in half. I pre-make several of these to have on hand and making more throughout the year is a breeze. Whenever we need a thank you card for someone I just have the kids sign the inside of one of these. It is an easy, cheap, and personal way for my class to show our gratitude to others.