Can't think of any inexpensive sources of soil that are trustworthy. Some contractors might be willing to give you some "fill" but you never know what is in it. I suppose you could make your own "soil" by piling up and composting a lot of organic matter but that is a slow process.

I'm still thinking about your hillside.
How much flat (more or less) space do you have at the bottom of the hill? You need to start from a stable platform. If you have some stable ground to work with at the bottom of the hill you can build your first terrace course relatively easily and add additional levels on top of that one. Remember that the trick is to let the water out but to keep the soil in. I'm wondering if some wire gabions would be useful for your project. Maybe some sort of willow stakes or some other small tree or shrub that is used for hills?

bob, by willow stakes do you mean using sticks like a fence? Hmm interesting idea.
The more time I spend on the hill the more I see possibilities.

Willow stakes are dormant cuttings from willows that you jam into or partially bury in the soil. When they break dormancy they take root. You can buy them from Ernst Conservation Seeds and probably many other sources. If you want to come to my church in White Plains and take a few cuttings of red osier dogwood let me know and you can do that too.

http://smg.photobucket.com/albums/v48/timesup/?action=view&current=1166715046.pbw

Unable to view your photo(s). The link you posted takes me to photobucket, but after registering I still don't see how I can view your pics. I have a downsloping lot and my front yard slopes down from the street to the house. I'm looking for ideas on establishing a hillside garden. I have a 40'x40' area that was covered with juniper groundcover that I hated and had removed. Thought your photos might have some interesting ideas.