Around here, patio grade, what they call locally anyway, goes for 75 a yard. Same strength as redi mix or so I’m told. So that’s roughly twice. I think it’d still pay it considering how much mixing would need to be done for that much concrete. Especially if mixing by hand.
I have a nice mixer, holds 8 60 lb bags at once. Two wheelbarrows full.... If you use a truck, you need a pump as well. And a crew to move it around.....I do this by myself....4500 psi is what I am using....