How much do landscaping rocks cost? On average, most landscaping supply companies are going to charge either by the ton or by square footage. Other factors may include the size of the rocks, type, the amount needed and company them. How Much Do Landscaping Rocks Cost? | Please note: You are currently browsing img decorative rocks lowes lovely rock and gravel for sale 28 that is 1600x1200px in size. This image is listed in decorative garden rocks lowes category. How Much Do Landscaping Rocks Cost, 1600x1200 in 350.54 KB.