"Scalloped" (hollow bottom) is cheaper; "Solid" is stronger and looks like real wood from the side.
If you want a specific brand like or Trex , use the "Where to Buy" tool on their websites. where to buy composite decking
These sites offer massive catalogs and specialized hardware (like integrated LED lighting). "Scalloped" (hollow bottom) is cheaper; "Solid" is stronger
Staff can usually help you calculate exact board counts and provide structural advice. "Scalloped" (hollow bottom) is cheaper