I should probably add what we did for $350
We had a front stoop, about 6'x4' that was sort of slanted a few inches, beyond that we had about 6' of sidewalk that was cracked (in two places, one in the middle and one from the stoop where they were once attached) and then a corner and another 15' or so of sidewalk that was leaning. That was it. So picture a 15'x6' "L" with a few stairs and a landing in front of the door.
Our mudjacker guy rolled back grass around the "L". Then he put mud mix under the front stoop (probably about 5' of empty space under there were poor bunnies who were evicted lived once), put mud mix under the 6' segment with the cracks, and under the long 15' segment to bring it back up as well and a bit more mud in front to prevent sagging after settling. Then he put more topsoil above
that and rolled our grass back over the new topsoil. It probably took him 2/3 of a day (8am to 2pm) for $350ish.