Older children of coaches in attendance are also utilized. No child care fees. Children are fed when the tab room orders food. The tournament absorbs the cost. Sacramento City College uses college students who have experience with children of different ages.
Fees go toward costs and, if necessary, care providers.
You could allow coaches to staff the child care in lieu of judging obligations or a rotation system. A room near the center of the tournament allows parent drop-in. Be sure the room is removed enough from activity to allow for quiet time and naps. Move chairs or desks to the perimeter areas to reduce risk of bumped heads, etc. This will create a central play and activity area.