Not many people have perfect garden soil when they start out their gardens, unless they had a hardcore gardener living their prior, live in rich wooded area or made raised beds and filled it with the finest compost.
HOWEVER, most people don't simply because the land that their house was built on typically was just meant for that, a house, and not with the thought in mind a person might want to grow wonderful luscious vegetables on the property.
Worse of all, I have noted that many houses seem to have clay trucked into the yard and foundation, my only assumption being that it eventually forms a stable surface for the house and boring landscape plants. I only make this assumption because every house, especially the new ones that I've dug around in ALWAYS have a about a foot of clay on top before I hit anything resembling real delicious soil.
At my house when I began gardening, it was all clay, well still is other than in my raised beds. It's taken YEARS before it has begun to look even vaguely good and amendments up the wazoo are still in need before I get that cake-crumbly goodness that I see and salivate over in other gardens.
As I am cheap, and most everyone likes to not have to invest so much money in anything to get a lot back I just wanted to share this awesome link on cheap ways to amend your soil. I felt like I really couldn't add much to the contents of this link other than some personality and sometimes I think you all might want less of that ;)
Where can you get Cheap Natural Fertilizers and Soil Amendments?
In addition here is another excellent link talking about the NEED for inexpensive gardening in Mexico City slums that will prove that absolutely anyone can garden on the cheap, and it should not be intimidating, but really a way of life. At least a pot of salad people, please!
-Organic food production in the slums of Mexico City
Have a lovely day!