Another idea for a classroom of valentines: Start with a 4" x 6" piece of paper. Bring the 4" ends together and adhere with good, strong adhesive to make a tube.
Glue one end of the tube closed.
Crimp the end shut. Crimping helps the end stay glued and makes it look more like a real sour cream container.
With one end still open, insert your candy, fortune, or other prize. Two or three candy kisses fit well.
Folding the tube the OPPOSITE way of the other closure, glue and crimp the container closed.
Lastly, decorate as little or much as you like. These are always a hit, and they're cheap and easy to make. The only drawback is that the containers are ruined when torn to get the treat out.