Every concrete slab that may need repair presents its own symptoms and problems. Each situation is different. The guy next door to me had piers put in all around the perimeter of his house. He had concrete push piers installed under a 2,000 square foot single-story house and he said he paid right around $7,000. We live in the Dallas area.
But the guy down the street in pretty much the same sized house only needed piers under the east and south side of the slab. He also paid close to $7,000 for concrete push piers. However, two of his piers had to go under the driveway. Maybe that added to the cost.
The number of piers required and the type of piers used for underpinning are two of the variables that affect the cost of foundation repair. Steel piers are generally more expensive.
This is one of the reasons the cost of foundation repair varies, and why the prudent home owner gets bids from at least three different foundation repair contractors. Spending a few hundred dollars on an inspection by an independent structural engineer is a good idea as well.
The Dallas Morning New recently ran an article on the damage to slab foundations caused by the shrink-swell clay soils and the weather in North Texas. The piece also touched on costs of foundation repair and how the lowly soaker hose is indeed your friend. Here is a link to the article.