I'll never forget a few years ago flying with one FO. With a small child and wife on maternity leave, she issued him $18 from their tight budget to last him through a 4-day trip. $6 went to pay for parking at an airport two hours away from where he commuted to fly his shiny RJ.
That left him
$4/day to live on!
He did have a loaf of bread and a jar of peanut butter that he brought from home, although the bread started to get a little moldy by the 4th day.