I understand companies have to make money but you are essentially paying for a hole dug in the middle of your garden (raised garden).
Now you can do the same thing with or without a hole. I have buried old veggie greens in The middle of my planters and works just fine.
You can use any type of container with the bottom cut out and smaller holes on the sides. Keep the cover to keep pests and animals out.
While we’re on the subject. Toss your veggie scraps in a blender to help the breakdown process work faster.
For those with fabric containers remember you are keeping worms out because they can not move up into the fabric pot. Poke holes or cut U’s and fold it so worms can migrate. Or catch them and toss them in the pots.
To get kids involved grow strawberries (everbearing or day neutral)