Step 1: Find a Friend
We recycled some old bricks in the yard. Many times people give them away. Word search bricks on craigslist if you don't have any. It is a great way to recycle what might go in a land fill! These bricks have been sitting in the back of the yard for 20 years or or so.
By the way, brick is the best option because it holds moisture and air which will keep the couch soil very healthy! Plus, it will drain well unlike concrete.