Gravel cost per square foot. Gravel costs $0.50 to $2.50 per square foot on average with coverage 12" deep (a cubic foot), depending on the type. Base gravel, crusher run, slate, shale, and crushed concrete cost $0.50 to $1.50 per square foot.. Colored and decorative gravel cost $2 to $4 per square foot. Gravel delivery cost