Smash cakes are a fun idea for first birthday parties. Many will order them for first birthday portrait sessions as well.
We make our smash cakes out of our mini cake, a 5" cake that we can decorate to any theme. They are typically $20, however cost depends on the final decoration.
Smash cakes need to be ordered along with all other occasion cakes: 1 weeks notice during wedding season (May - November) with a minimum of 4 days notice during off season. However you should always inquire about ordering time as it can vary even during off season.