For jobs larger than mix-your-own, and smaller than having a delivery:
In my area (Massachusetts,USA) you can get a trailer-load.

Here, its called "Yard at a Time" and the trailer holds up to 1.5 yards.
I added an extra sack of cement to their regular mix and towed it home (I
have an F350 1T)

It ended up costing the same per yard as the delivered stuff but I didnt
want a 10 ton concrete truck on my new concrete driveway.

I backed it into the garage and over to the back door where the 'chute' was
near where I needed it..step/slab just outside the door.

R