Best way to make $40 stretch Friday to Monday for food for a 4 year old boy?

Getting my son this extended weekend but only have about $40 for food until payday. I could probably eat some leftovers here, ramen or whatever elsebi could find but food dedicated just for my son I only have $40 currently (unless I'm able to work a side gig or something in the meantime) so wondering of some foods I shoumd get to make it work? Strong thanks