This is a birthday book certificate that I give to my students to use on a Scholastic book. I then fill out the coupon from Scholastic myself, and this way, they don't lose the certificates I pay for!
This is a publisher file you can edit. The version I give to my students has my school logo in place of the clipart I've included here. You might include an image of a book or customize it some other way. It's a good starting point, though!