Here are some cute Valentine cards to print for your kids. They are formatted to 4x6. I just uploaded mine to Costco (you can also just print them from your printer), cut them in half and added some candy pieces to it. So easy! You can't tell, but the one on top has a white border around it and sometimes Costco cuts off a tiny portion of the 4x6 print. If you're going to upload them, try cropping it a little bit to see if that will help.
Happy Valentine's Day!