Well, they went over really well. And they were cheap!!! Ahem, I mean, affordable!!!
Another time, I blew up helium balloons (from a small helium tank I got at a party store for $20) and I inserted little folded up notes. The kids had a blast catching and popping the balloons to read their "prizes" which were all no- or low-cost. (Three piggy back rides, 2 funny jokes, 1 spinning around, penny candy, etc.)
I also did this without the helium, too. The kids still love all those balloons on the floor. They loved to walk through a red balloon fog! Not all balloons contained prizes either.
Balloons are pretty cheap.
I wish I could make up special cards. You'd think that I'd be able to come up with some pretty profound Valentine's Day cards, as a writer and all. But my emotions overwhelm me and I get all choked up and words just seem so limiting. Then, I resort to those corny Hallmark cards like all the other desperate people standing in front of a card rack on Valentine's Day.
I wish I were more poetic.