Gardening on a Budget: Soil

Especially if you're a container gardener who wants to grow organically, the cost of soil can start looking pretty high. So let's look at a few ways to cut back on that cost.

1. Screw the fancy "organic" soil that companies like Miracle Grow sell, because it's way expensive (and not all that great, in my experience). Instead, pick up those 40 pound bags of cheap soil with "compost" in the ingredients rather than "fertilizer." They're sometimes cheaper than that small bag of "organic" soil, and I've had great luck with them.
2. If you're growing in-ground or in a raised bed, you don't need to add new soil every year. Compost is usually all you need to add.
3. If you're a container gardener, you can often reuse your potting soil. The most important rule is to never reuse soil from diseased plants -- that stuff needs to be thrown into the deepest darkest corner of land where you won't grow anything you care about. If, however, your plants were healthy and strong, you can take out the old plant, mix in some compost, and reuse. Some people feel it's necessary to bake the soil (yeah, as in baking it in an oven), but I've never bothered. When I'm not 100% confident about reusing a pot of soil (often because a cat used it as a litter box!), I'll use it for non-edible plants just to be safe... or I'll use it to fill in holes in the backyard.
4. Don't use containers any bigger than your plant will actually need.
5. Use companion planting in you container garden. For example, why put basil plants into their own little pots if you're also growing potted tomatoes? Basil and tomatoes love each other, so go ahead and tuck that basil plant into the corner of the tomato's pot.
   

As a side-note, I don't recommend just sticking yard dirt into a container, especially if you plan on bringing it inside. Part of the benefits of container gardening is reduced pests and weeds, and yard dirt is full of them.