When I was in kindergarten (half-day) I went to a lady's house for the
afternoon-I remember she used to give me bananas sliced up in a little
milk with sugar on top. I enjoyed it.

Bananas are cheap, bulky, food and you can jazz them up many ways
cheaply-a few choc chips, caramel chips, nuts, jelly, pb, milk, etc.

Big containers of cheap ice cream from Walmart or Aldi's provided you
have freezer room.

Cheap generic anything looks more appetizing if you remove it from its
generic packaging and store it in your nice containers.

Do their father a huge future favor and get each kid a
toothbrush/toothpaste and supervise and teach good brushing habits.