The best soil one can get is loam which is about 45 percent sand, 25 percent silt, 25 percent clay, and 5 percent organic matter. Loam, however, is not all that available so most of us make do with what we have and add lots of organic matter.
So where in the United States are you and what kinds of organic matter are readily available for free? Before spending a lot of money on non renewable resources I'd look for what is locally available, for free.

"which probably has petros and other chemicals anyway,"

Do you have some specific reason to think that, in the case of your location?

@ kimmsr - Thank you for that that makes sense - I am 7b so we have lots of clay. I am leary of buying soil so I don't know even natively the best way to go but that's not said to discourage myself, I just don't know good resources. Once I find a good source do you suggest any amendments? I have heard mixed results about Mel's Mix and I really want to start off on the right foot .

@ pnbrown - I have tried three popular brands that were for my area that I later read had petrochemicals and complaints about dismal vegetation growth. I then tried Happy Frog which was good but VERY VERY expensive for a small bag. I gotta find a happy medium.

Unless previously contaminated as a dumpsite or old gas station/car repair yard, native soil should not have any significant levels of petrochemicals. Neither should most bagged potting soils. Most are tested for these sorts of contaminates. Bagged composts can be a bit different but generally are free of petro contamination although may have other, nondesirable ingredients.

What kind of soils you should be looking at depends on how you tend to garden - raised beds generally require a somewhat different soil than in-ground gardening. If using raised beds, a garden mix is ideal. Typically these are 3-way mixes of some sort of loamy topsoil, compost and a drainage enhancer. These can be purchased bagged but are far less expensive purchased in bulk.

If gardening in the ground, just adding a reasonable quantity of compost is often sufficient, provided your current soil drains well. Compost is typically nutrient rich and should provide all the nutrients required for good healthy growth and crop production. You may need to supplement now and again with a fertilizer if you have a long growing season.

I long ago resigned to the fact most good things require time. I have soil,compost and different experiments in varrious stages of completion on any given day. The most recent project that I expect to produce a large amount of imporved soil involves tree limbs. I feel soil is idealy liveing and active,therefore bagging and saving soil isn't optium. I made a mound of soil,wood,leaves,grass and native soil much like hugelkulture 4 years ago. What I pulled out and used last summer was better than any product I ever got from a bag. I alow neighbors to dump their tree branches and other organic material on my place. The back side of my garden is piled high with tree branches,leaves,hay,pumpkins and cardboard covered in 12" of soil growing vetch and clover. The point I am making is that improving your soil is better than importing soil.

@ gardengal48 & klem1 - so since I am going to be doing square foot gardening what would be the best to start with now and in what amounts? I have seen bulk cow manure on Craigslist but I know that is not the same as soil. I didn't want to rototill but it sounds like what I may have to do? Please correct me if I am wrong.

need to know something about your native soil type.

Add to whatever mineral soil type you have now organic matter, compost, shredded leaves, cover/green manure crops, enough to get the amount of organic matter in the soil to around 6 to 8 percent of the soil. It really matters no whether your native soil is sand, silt, or clay it most likely needs organic matter.
Find out where, your state universities Cooperative Extension Service can be of help here, to have a good reliable soil test for soil pH and major nutrients done. Then dig in with these simple soil tests,
1) Soil test for organic matter. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drainsâ too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer your soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
to see where your soil is.