Earlier quoted context omitted.
The article also excludes the cost of electricity/gas to power the stove/microwave, the cost of water to cook e.g. pasta and clean the pans after, the cost of the pans amortized over your meals, the cost of plates and utensils... If someone else is paying utilities (say, your local university, or your landlord), and you already own kitchen equipment (say, hand-me-downs from your mum) perhaps this is a reasonable assu…
Actually, in first world, not even an homeless gain less than 2$ per day. So we can safely leave all the expenses for fuel and cookware out of the math.
The extreme poor area I lived in was also full of drug addicts who spent all night going through trash bins and cleaning out anything of value to support their habit, so if your plan is to mine for recycled bottles and cans to return then you're in for a surprise when you find out that hustle has already been cornered by violent drug addicts and alcoholics who won't let you near their garbage 'turf'.
They also rob each other when they walk out of the recycling depot with cash in their pocket. Since you live in an alley you don't have security