With labor and materials, the price range for a retaining wall block runs between $750 to $1,500 for a wall that is 30 inches high and 20 feet long, as of 2015. The materials for this project, which are most often pre-cast interlocking concrete stone blocks, cost $15 to $30 per square foot. Most do-it-yourself materials cost between $10 to $15 per square foot.
If using stone, the average price is $25 to $40 per square foot, bringing the total price to $1,250 to $2,000. A wall that uses poured concrete costs $30 to $40 per square foot, bringing the overall cost to $1,500 to $2,000.