We're fond of these valentines because they're simple, fun, and inexpensive.
Cut a heart from card stock (ours are 3 1/2 inches wide and 3 1/2 inches tall). Punch 2 holes in the heart, one toward the upper right and one toward the lower left. Use markers to add a message.
Insert a Pixy Stix through one of the holes. Gently bend the card and slide the candy out through the other hole.
To make the arrow, sandwich 2 heart-shaped stickers (we got ours from Oriental Trading Company) over each end of the Pixy Stix.