I do not do concrete for a living, but I have had several slabs poured on my farm-ette (16 acres) lately, so I am a little familar with the topic. There is more involved here than just the price of concrete and how much you need.
You first need tractor or grader work. What are you going to do with the dirt / material that is removed? Do you need it hauled away, etc.? In VA are you dealing with rocky soil, etc.? Equipment, trailers, diesel fuel, compactors, insurance and employees time all cost something. How easy is the site to access? Do you need footers dug? Will you need fill dirt and if so, where will it come from?
Here, you can rent, with delivery and pickup, a small tractor with front end lift bucket and a box blade for around $175 or so for a day (up to 8 hours on the tractor) Fibermesh reinforced concrete runs around $85-90 a yard. You can price mesh and rebar at Lowes but they are not very much.
If you live in a busy market (spring is almost here and things will start to pick up very soon) you are also competing with other jobs for a contractors time. If he cannot make any money on your job, why should he show up?
There is no way to see from here if that price is reasonable or not.