at our other house, we used standard 6 ft cedar or fir (?) fence boards, (the 6" wide ones) which are about 1/2" thin, and some of the beds bowed slightly, so we then used wood and rebar pieces and put ample stakes in the ground to stop the boards from bowing outwards. We made the raised beds either 2 or 3 boards high. (the ones pictured here are 2 boards high. The bed in the back is strawberries, with a recycled screen panel over it- to keep the birds from eating all our berries! The width is 3 feet- because that was 1/2 a fence board and anything over 4 foot wide you have a hard time reaching across (especially if you are vertically challenged, like I am). It takes 6 boards to make one of the short beds- so about $12 plus stakes and wood to nail corners to.