The only cost is the sanding discs and glue and nails to attach to the wall. I get pallets from a few contractor friends in the area. Use a skill saw to cut out the boards. Take them to the chop saw to square the ends. Run them through the table saw to get the same width then I orbital sand each one. Start 80 and work up to 220 grit. Paint the wall a dark color. Put up the pallet pieces with a spacer like you would tile. Attach with adhesive and a couple finish nails. The final outcome looks amazing. This is in a $800k home and the owners LOVE IT.