How to Make a $10 Raised Garden Bed Tutorial. Celia's update: I had Brent make this for me a few weekends ago; It was super easy and I think it will be perfect for my garden. He used 2x12 lumber, and I think it was a bit more expensive than the $10, but it was still pretty cheap!
Frugal Gardening: Four Inexpensive Raised Bed Ideas
I did this because there is no digging in my rock solid ground. Did not cover the holes but use them for herbs and annuals. I also lined with weed barrier cloth and used rebar in several places for stability. I love it and makes maintenence super easy.