Some folks on the internet say to use very large containers, but some of my best broccoli last fall was grown in sinks I got at Construction Junction, which were relatively shallow. That might have been because I used 50 percent manure for those containers. I also used cabinets from Construction Junction, and those plasticky but puncturable recycling containers. With more durable plastic, I drilled holes for drainage (in the cabinets as well. I used bricks and pieces of wood to elevate the containers for better drainage, which the internet recommended. Also look into feed sacks (apparently free at some supermakets and cut down on weeds) and kiddie pools. Oh yeah, those cabinets will need two people to move when full of soil, and might be treated with formaldehyde which some think can affect your plants or you.
Good luck,
Nathan from Permaculture class