If you want to buy a box of Cheerios, it's pretty easy to figure out how much it costs. You walk in to your local grovery store, find the cereal aisle, and look for the Cheerios. Right below the box, it tells you the price.
When you want to buy some pervious concrete, unfortunately, the process is not as easy. At a minimum, there's a team involved: a civil engineer, a contractor, and a concrete supplier. Each member of the team negotiating their price with the purchaser. Add into that variables such as project size, geometry, and market.
Often I'm asked, "How much does pervious concrete cost?" The Georgia Coastal Stormwater Supplement describes it well, "Although permeable pavement is generally more expensive to install than conventional pavement (e.g., asphalt, concrete), it can provide measurable reductions in post-construction stormwater runoff rates, volumes and pollutant loads, which can reduce the need for larger and more costly stormwater management practices, such as wet ponds and stormwater wetlands, on a development site." Under section 7.8.4 it reiterates the point by describing the cost of pervious concrete as, "Relatively high construction costs, which are typically offset by savings on stormwater infrastructure (e.g., storm drain system)".
As one more reference, this recent article about the pervious concrete street in New Orleans describes the cost of the pavement (just the pavement -- not the pavement plus stormwater system) as 10% more than conventional concrete.
