Concrete delivery trucks hold (depending on size)about 7-8 up to 10 or so yards. I don't think HF sells one that does even 0.5 yds.
I am on my second one of the 3 1/2 cubic feet model. They work, just don't let one fly over the side of your pickup during acceleration or cornering or both as it can be damaged beyond economic repair.
Also be careful maneuvering it so as to turn it over as it can be damaged.
I have done some fairly large projects with small mixers. You need to plan for how to handle "cold joints" as they will be inescapable except for narrow projects like sidewalks.
You can reduce a slab pour to a series of small pours and have continuous rebar running through the entire slab. If having say4x4 ft sections tied together by rebar making up your slab will work for you or a series of parallel 4 ft or smaller strips (like adjacent sidewalks) then:
Drill clearance holes in your forms to pass rebar. Drill these holes larger than the rebar by at least a saw kerf as after drilling the holes you need to rip the form down the centerline of the holes and then reassemble the form with deck screws for ease of repetitive assembly/dis-assembly.
You pour a section or a strip with the rebar "running wild" through the drilled holes. After that section has firmed up you remove the forms and set them up again one section width over and pour that section... lather, rinse, repeat...lather rinse repeat...
This method will allow you to pour large projects a little at a time so long as the finished work being in pieces held together by rebar "works" for you. It will do garage slabs, patios, etc. I haven't used it for slab-on-grade residential floors.
Here are pix of my latest concrete pours. I'm forming a retaining wall behind house but haven't poured any concrete for it yet.
From left to right the pix are:
1. Made sidewalk wider. I planned for "wall hugger" heat pumps but ended up with units requiring wall clearance so needed to widen sidewalk for ease of getting by with hand truck or cart of materials.
2. Widened apron to have pavement out to retaining wall.
3. Foreground sections are original apron. In the background are a couple sections I added (the curved one and the one to the right of the curved one. These were poured on different days.
You can use a masonry bit in a hammer drill to drill holes in existing concrete to put in rebar to "tie" the old work to the new.(dowling)
Patrick