These days so many creative families are building raised garden beds out of old pallet boards. So many local businesses have leftover wood pallets that get thrown away or picked up by their local trash company. Simply stop in or call a local business to see if you can pick them up at no cost! I had great fun designing large deck garden beds with leftover pallet wood from a local distillery. I now have tons of sweet cherry tomatoes in all colors and lush herb plants growing tall. Talk about farm "front deck" to table fresh!  Pinterest has easy guides to building the boxes and how to plant healthy flowers, herbs, and vegetables.
Happy Building!