This might not be the sort of answer you're looking for but Craigslist has a TON of people giving away horse/dairy/goat manure. Some will deliver for free!

Here is a link that might be useful: craigslist phoenix

I grab loads of coffee grounds from starbucks.

We use the dead leaves from the trees, coffee grounds, kitchen scraps such as onion peels and spoiled vegetables, weeds, etc.

You're right. It's hard to make enough compost. I've got 2 compost barrels and I must throw in tons of stuff and much of it seems to evaporate into thin air. I threw a phone book in it and it's just

Free manure is available from nearby farms and just wet it down and it's ready in about a month. My zucchini planted in straight composted manure is 4x's the size of the same variety in potting soil with top dressing of compost.