Ok, you've already convinced yourself that your goal is impossible......you can't grow your own food, can't afford to buy organic clean food, and can't source clean food locally, you just can't provide clean food for your family. You've given yourself an F grade before even trying. You have failed before even starting. Ok, take a deep breathe and throw all that out the window. Next......slowly, gently take you're first baby step to attaining your goal. Yes, baby steps work. I know because I've been there, done that.
If moving isn't an option at this moment, there is still plenty you can do to start on your journey. Step one is to change your expectations. Don't expect to instantly change over to 100% all natural food this year. Set yourself a more realistic goal....a baby step. A small baby step to start.
Not knowing your situation, I can try to offer suggestions but can't be specific. Start out with some of the easier crops to grow, perhaps peas, green beans, Chinese greens, turnip greens, chard. Don't plant a lot. Just a few of each until you become comfortable tending them successfully. Once you find you can successfully grow the easy crops, you may opt to expand the planting. Even on a tiny city plot, those 5 veggies can produce quire a bit of interesting food. They can be grown among the flowers and shrubbery. Eventually you may opt to grow just veggies instead of flowers, shrubs, and lawn grass. (As a side note: my mother grew up in a row home in downtown Philadelphia. Neighbors there grew plenty of greens, turnips, tomatoes, and potatoes which they shared among themselves. Neighbor's with shady backyards...those backyards were extremely tiny....grew greens and turnips. Those with sunny yards grew tomatoes and potatoes. Neighbor's then shared their excess among themselves. My mother said that they had plenty of things during the growing season to add to the dinner table.)
On a small plot, you can experiment growing in containers, thus utilizing unused concrete walkways, margins around a driveway, margins around the house foundation, etc. You can look into growing vertically, by trellising pole beans or making vertical planter boxes. You can try patio style veggies in hanging baskets and window boxes. There are some really cute veggies suitable for this -- peas, tomatoes, extra dwarf bok choy, fingerling carrots, etc. I've seen examples where people made a rope trellis as a "roof" over their patio, and runner beans, pole beans, pumpkins, winter squash, or other long vine crops were grown on that trellis. I've seen trellises made up against the side of the house, with vining veggies trained to grow up them. I've seen vining crops trained up the side of a tool shed, then spread out growing atop the roof. I've seen portable container boxes lined up on a shed roof, thus growing container veggies in a space normally not used. There are many other possible ideas to use depending upon your property.
The whole idea is to start. Start small. You can build up from there. Even in tiny spaces, you could grow quite a bit of food by being innovative.