If you are receiving food stamps and healthy eating is a priority, I'm not sure what kind of health store you are buying from. Are you buying organic, fair-trade? That can seriously limit your budget. You can still get healthy food that is, although not organic, still nutritious and wholesome.
There IS a huge social issue with affordability and accessibility to healthy food for lower income people, and yes, if it's cheap we're gonna buy it. And when so many people buy their product, they can afford to decrease prices and still make profit. My neighborhood has a McDonalds, Subway, Quiznos, Starbucks, fried chicken joint, pizzeria and a fish and chip place, all within a block of my house. If I want to go to a grocery store I have to take a bus. There is OBVIOUSLY a problem with that. And I really feel for you, it's very hard to try and get healthy when you hardly have the resources to do it.
There's a way around it, kinda, and I learned that while in college with virtually no $$ for food most of the time and working closely with people who were running the student food bank. This wasn't decades ago, I'm talking 2008.
My grocery list would include things like dried legumes, brown rice, buckwheat pasta, peanut oil, herbal teas (instead of juice), yogurt, frozen peas, canned corn (unless in season), rolled oats, and seasonal fruits and vegetables, because they're cheap when in season. Potatoes, carrots, celery, turnips, mushrooms, leeks, cabbage, Brussels sprouts, apples, pears, peaches and plums are usually good choices around this time of year, and most don't spoil quickly. It changes year-round though, so you can vary what you eat too.
There was a lot of good advice on this thread, I hope you find what works for you