Valentines at preschool?

My kid’s preschool is going to be doing a party for valentines and asked parents to bring in a valentine for each of the kids (20 of them). I hate getting cheap plastic junk that’s going to be thrown away so I was thinking of getting a small book with a card and a piece of chocolate. The teachers didn’t really specify what they mean by ‘valentine’. The books will cost me a little more but if there’s an excuse to give kids a book then why not? Is that too extra? This is my first kid and i went to school outside of US so I’m not sure what the standard is.