How much to add is largely dependent upon what your goals are in using it. Do you wish to use organic matter alone to provide all the fertility your next crop needs or will you also be using fertilizers (organic or synthetic)?

How much organic matter does your soil currently have? Generally 5-6% organic matter is considered good, but some go much higher, particularly when the OM is meant to provide all the plant nutrients over the season.

Are you trying to improve something about your soil such as it's tilth/texture? Increase water retention? Improve aeration?

Generally speaking I would suggest adding 1 inch over the surface of the entire garden. Tilling it in or not is up to you. Tilling it in gets it in the soil faster, but it will get into the soil either way.

After this is done you can compare how this worked out in terms of what your goals in using it were, but I think 1" over the entire garden is a very reasonable starting point.

I would estimate that covering 1,000 sq. ft. an inch deep would require about 1½ yards of compost.

I got municipal leaf and grass compost for $10 a yard [large] . It looks great and likely is but contains about 8 to 10% crushed stone!....plus some crab grass seeds.

I figure that a few stones were raked or sucked up with the leaves. When fully composted the leaves are about 1% the orginal mass but the stones...uh, don't compost...so the stone effect is greatly multiplied. They claim to grind and screen the compost, but it definitely needs further screening...which I did on the second load which gave me about 400 pounds of stone.

I'd try to prioritize: compost is heavy (damp, usually) and already broken down quite a bit. If your soil is compacted (heavy clay), I'd break it up a bit with something slightly larger first - that way it will take some time before it breaks down and you need to add more. (Spaces are important - organic material stores water, then when evaporation takes place, spaces provide air so plant roots aren't suffocated.) Mulch (even purchased bags, if you're desperate enough - like moi), dry leaves, straw all work. Depends how expensive - $, weight, availability) a material is for you. Compost takes a while to make, so usually it's easier or cheaper to get your hands on things people consider "scrap".

Then, once you have some spaces in that soil, I'd begin to enrich it. That's where compost, fertilizer, etc. come in. Keep in mind that water in any form will help nutrients filter down through the soil. Is that what you want right now? Are you going to plant fall crops? (I'd bet not where you are.) If not, those nutrients will filter down when rained on, and your plants' roots won't benefit from it next spring/summer. Leaving it on top, or waiting, might be good. Again, it depends on how difficult it is to get ahold of and move to your place. This fall and again next spring would be ideal.

as much as you can haul or afford to have hauled in

Here it costs $7/cy and is high quality. Delivery costs $50 so think carefully before you pull the trigger. See, for example, if your neighbors want some to split the delivery cost.

Here the compost is broken down enough that as earthworm food it is past its prime. As a medium for starting seeds, in place or indoors, it is excellent, specially after it has weathered a bit. For one year fertility requirements, two to four inches will be enough, two for radicchio or carrots, four for cabbage.

Finally, consider if you want to have raised beds or not. You probably need them if you plan to go above 3 inches, lest you want all that stuff wash in the paths every rainstorm.

Compost will also behave differently on sandy or clay soil.
On sand, biological activity mix it intimately with the sand underneath within two years. But on clay it will sit on top for a long time. This is not necessarily bad, it means that direct seeding will be easy for a long time, if you add some fertilizer, with the little roots having enough room to grow strong before piercing the hard stuff underneath.

IMHO, more is almost always better, and I would raise the beds and fill them to one inch of the top. I do prefer to throw in some unfinished compost (kitchen scraps, mixed with leaves, relatively fresh manure) every two years at least so that earthworms stay there. Because this is basically earthworm food, much smaller amounts are needed. They do most of the tilling and mixing that is needed to keep the soil in top shape structurally. Further, with winter freezing they tunnel down to 2 or 3 feet, which is something no tiller can give you.

I got shale but I've been growing alot of vegetables in it. i'm just thinking i never enriched my soil so now that i know the free compost is available, i should get some. my beds are raised, i dug out paths that are anywhere from a few inches to one foot deep. i am near to the point where i only want to till the beds anymore. it took me too long to build those high beds so i think never to fool with them, just rotate the crops every year and hope for the best.

i was gonna buy those plastic tubs from Lowe's and fill them up, I got an old sedan i could make a few trips back and forth. tumble the stuff over and spread it. i might ask the guys who work there if they want to make few bucks and deliver a truckload, i think i can use that much due to shale soil i have.

more later.....i'm reading all your posts. oh by the way, i have only used mirale grow throught the years if anything.

Well, $10/cy is not free but is certaily a good deal. If you are looking for a bargain, borrow a truck from a friend, relative or neighbor. Also if they can deliver like 4 cy for the same 50 bucks, you can have it delivered. This way a cy will cost $22.50, stil a good deal, provided you have a need for that much compost.

Our city does this too, I live 3 miles out of town and the sign says free for residents and with in 3 miles of town.

I get it by the truckload. One day a week they will load it for you. This is the day I go! Sometimes I get 2 or 3 truck loads that day. I use to spread it on all of my garden, however I have started, out of time constraints, till in my beds and just spread in the rows. I till two tiller swaths, put down 1 or 2 inches of compost, hill it up and till ones then plant. My results are really good and it saves me time.

I dump free municipal compost, leaves, and used coffee grounds (also free from Starbucks) in my beds in the fall, then just turn it over a little in the spring as I plant out, pulling out any stray sticks or stones. I've never tilled my beds, but they have great soil... the earthworms mix everything up as they work their way through the soil.

City compost varies widely. If it looks dark brown and rich, take as much as they'll give you. Compost is probably better and safer than fresh manure.

Thanks Jessica. It sounds as though if i put compost on my garden, i dont need the manure. I'm working on a truckload and I'm gonna spread it as thick as I can before the cold weather comes.