Just because you have no cash or valid credit card doesn't condemn you to a steady diet of ramen and potatoes. You can still indulge your taste for organic produce, ethically raised meat and fish, artisanal bread, cheese and chocolate.
No, I'm not advocating dining and dashing (except on special occasions). Nor am I suggesting we return to the old ways of hunting and foraging for sustenance (a practice often referred to as "stealing" these days). This may seem counter-intuitive, but poor people in the know go to Whole Foods. Not to shop, mind you. They make a meal of the lavish, liberally placed samples.
Sure, there are other places that offer free samples, I've tried them all. Costco's may be varied and tasty, but they're mass produced and of questionable origin. Worse, the security guards at the door make takeout impossible. Farmers markets are seasonal, limited to once a week, and hard to get enough for a full meal. Trader Joes' disappoints with limited choices and erratic service and quality --one day the mushroom risotto is ready in its little cup, steaming and perfectly al dente; the next, you have to wait five minutes for a mediocre, lukewarm chicken biriyani.
For quality and convenience, nothing beats Whole Foods. It's got everything from meat to fish to fruit to cheese and even vegan offerings. It's like the antipasto course at Trattoria della Arte in NYC without the ambiance and service. On Saturdays, they even give out cosmetic and beauty samples, so it's like getting a goodie bag with your meal. 
Start at what I call the cocktail and hors d'oeuvres section, which is right past the cash registers. Savor a berry/green tea drink and nibble on salmon salad on crackers while exchanging warm banter with the lady passing out the samples. When sipping from the tiny paper cup, I try to maintain an air of elegance by keeping my pinkie finger extended.
The menu changes often, so it's always good to peruse the offerings before making a choice. You can't go wrong with the assiette du fromage (a sumptuous array of brie, chevre, cheddar, fruit and cheese doodles) available daily. I recommend stopping by the prepared food counter and asking for samples of the broccoli, coleslaw and grilled veggies, especially on days when spinach dip just isn't going to cut it in the roughage department. Last time I was there, the dessert offerings included broken cookies, cups of pie and pieces of chocolate Easter egg, all worth the extra calories.
Whole Foods is open for breakfast, lunch and dinner. Dress is casual, but shirts and shoes are required. You can dine in, but takeout is also available if you remember to line your pockets with plastic bags or get paper plates from the salad bar. Bon appetit!