@Harry Sax
It just occurred to me that winter coffee is the world's biggest hustle. Coffee is basically flavored water! You could probably set up a corner stand on a city corner, ideally near your financial district with a table and some chairs.
Budget
20 bucks on a used 2 level table.
100 bucks on a used espresso machine
50 bucks on coffee grounds
50 bucks on milk or creamer
50 bucks on sugar/Splenda
80 bucks on a printed, witty sign that you ripoff from an existing coffee shop from another city, from pictures found on internet.
100 bucks on speaker system to attract folks.
45 bucks on winter clothing.
5 bucks on containers to transfer tap-water from your home to the street corner.
100 bucks on a car battery to power the coffee machine
Charge $3 per cup.
Total spent:$ 500. Use remainder of 1k for resupply. Also some of that 1k should go to giving free coffee to any wandering police officers as a "thank you for your service" . Tell them to tell their friends. Permits will not be a problem.
If you pick your corner correctly; then you should double your original 1k within 5 bussiness/workdays. Caveat here is that your state must have cold winters so Texas, Lousiana, Arizona, and California wont work. You may be able to do a variation of this with snowcones if you are in a warm state. Your target demographic is those walking business people.