Rent here is 400$/month minimum - and that's sharing a room or splitting a house with 4 friends. Not counting utilities.
Food budget alone should be at least 400$/month as well if you're eating a meager 13$ of food a day.
You'd be amazing if you had less than 400$/month of car expenses including payment/repairs.
Then there's everything else. Health bills, insurance, internet, Netflix, etc.
$2-3 / day for food is doable (Cali groceries are a bit more expensive so maybe $4 here). Cut out all but the cheap meats. bread and veggies are super cheap (corn can be 5/$1 when it is in season)
no insurance. no internet (libraries are great). no car.
I never had expenses above $1000/month (not counting the month I paid $1000 to buy my first car) until I moved to the bay area and started making six figures.
There are a lot of small towns in America where you can rent for $350 or $400 per month.
I lived on a $50 per month grocery budget when I was 21 (maybe $75 today). Worked a part-time job that paid for my apartment, and worked as an entrepreneur the rest of the time.
I think it's pretty amazing how low your bills can be when you're really young, have no family, and little to no concern about health issues (I had no health insurance for a decade, never had a single health issue either, which is purely luck / genetics).
after rent, having no car (bicycle) and no data plan cut things down even more.
only real issue is lack of medical insurance.
was 5 minutes walk to nearest grocery and 5 minutes bike to work. Though in the winter I would walk (half hour) because biking on ice is deadly.
$650 a month? My utilities, insurance, and food budget easily exceed that, nevermind rent. My first job paid $35k/year, which was comfortable enough (in San Diego), but I was living paycheck to paycheck.
The problem with budgets like this is that they work for some people, not everybody, and set up artificial expectations (i.e. in terms of crowd funding or other capital). I am definitely an advocate of frugal budgets, but there is a line. I don't see $650 month working when you have a wife, kid(s), dog(s), mortgages, and/or car payments - but then again many independent developers are wise enough to not take on those things. I have all but the mortgage, and I consider my burn rate of $3k/month pretty frugal.