The best way to save money on food and insure your produce is pesticide-free is to grow it yourself! If you are in a state like Missouri where "soil" is a synonym for "rock," a raised bed garden is necessary. If we could find a way to sell rocks, we'd be rich!
I use Mel Bartholomew's book Square Foot Gardening. This is a raised-bed system of gardening that uses 12" squares as your planting guide. Raised beds can be made from many materials, but do not use treated lumber or old railroad ties, as the chemicals will leach into your soil. Even if you only have an old whiskey barrel, truck tire, or large pots, you can have a garden!
Our beds are about 10'x3' each. This allows me to reach into the garden and tend the plants without ever having to step on the soil; very important for plant health. By planting in square feet, it reduces the amount of weeds that are able to grow since the plants fill up the space and shade the soil. Plants can also be watered individually, significantly cutting down on weed growth. This method also allows many more plants to fill the same space as the traditional row-planting method.
Mel gives the soil "recipe" in his book, which is a bit costly to initially set up, but produces great results.
In our area--Zone 6--now is the time to plant your cool crops such as broccoli, lettuce and spinach. There is not much more satisfying than going out to the garden to pick your own salad!