This probably should be on the "Projects" forum, but since the 3PH mixer is the discussion, I'll just put it here.
There's another possibility I have used a couple of times. When I have a small job - maybe a half yard or yard - I call the concrete company and ask for a place to dump of the remains of what a truck comes back with. I might have to wait a day or two and be around during that time, but it has worked here. I let them know I expect to pay for the concrete, but that I don't want to pay for the minimum load. I suppose you would have to be within a reasonable distance from the concrete plant or job site, which I happen to be, and assure them that it's a "dump-and-go" job and make sure it is.
Duane