What says beach day more than a nice bowl of Honey Nut Cheerios and milk? What about a sentient, shapeshifting towel? Also, your get a free tiny beach ball in your cereal box. What happened to cereal box extras? Aired 1992.
In answer to what happened to cereal box extras, I bet the reason I've seen more mail-in premiums than free-inside premiums is because with mail-in premiums they can make one have to get multiple packages of their products (because they can make one need multiple proofs of purchase) whereas free-inside premiums one has to get only one product if the goal is to get the premium (because the premium is enclosed in the product's original box).