I've been hallucinating about installing a concrete pad of
about 1000 sq feet out the back. This would involve moving a
little bit of earth, but not a whole lot -- it's almost level,
and it's currently planted in grass. It would be intended to
accommodate a storage building and a patio, and it should be
able to be be driven on with an average size vehicle (say 4000
#). Clay soil, if that matters.

Would anyone care to take a wild guess at how much it would
cost me to buy this done?

Would anyone care to take a wild guess at how much it would
cost me and how difficult it would be for me to do it muself?
(Bearing in mind that I habe never done anything like this.)

Thanks!