If you don't want to use Apple's "Find My iPad" service, here's a free way to increase the chances that your lost iPad gets returned -- turn your lock screen wallpaper into a picture that displays your contact info.
Even if you have a passcode lock in place (which we recommend), your contact info is still visible.
It will only help your odds of getting your missing iPad back safely.
Create a new image in Photoshop at 2048x1536 pixels
Paste in a background image you like and size it to fit appropriately
Use the text tool to add whatever contact information will be most helpful to someone who finds your iPad