This can vary depending on the type of crack repair. If it is structural or if it is leaking. A good common example would be a poured concrete basement wall that has cracked diagonally down from a window to the floor 6 ft long, a non-structural crack. This could be repaired using a standard polyurethane product. A polyurethane kit would cost $140 to $215 depending on the size of kit purchased. You save on the labor cost if you purchase a DIY kit. This same crack repaired by an experienced foundation contractor may range from $400 to $800 depending on your location, the level of expertise and any other costs built into this repair such as overhead, warranty, labor and workers compensation costs etc. There is no average per ft cost by contractors, but the cost could be as much as 5 times the material costs.