I think that the one-off nature of this challenge makes it unworkable. The idea of starting from zero and cooking something on a budget is totally unrealistic for most people. We all have a pantry/freezer of stuff we've built up. Dipping into that stuff is just a part of how cooking happens for most people. Nobody pretends they have a bare cupboard and a $5 bill to put dinner on the table.
As for challenges, I've seen people talking about the "SNAP challenge", e.g. live for a month on a food stamps budget. I think seeing how people in various places face that could be interesting. We'd get to see what various localities' cheap eats are... Setting the challenge to a bunch of foodies, and allowing dipping into the pantry, would be a fascinating read and perhaps some inspiration. Watching somebody go shopping with a $5 bill and make a single meal is not so interesting.
