you can buy a cabinet at lowes or home depot,you will have to assemble it yourself,you can also make a frame out of pvc pipe and use plastic to cover it,I guess it all depends on how you want it to look,I wouldnt screw plywood to plywood it wont be strong enough and the screws will pull out.I scored a shelf unit that was in a store it used to hold soda its has adjustable shelfs and is super strong,all I did was cover it up with plywood and some doors on the front and now its my veg and clone box works great just have a few things I want to change to make it easy to work in.so theres an option for you you can use that metal shelfing and cover it whith what ever you want. good luck peace and grow on