Take any average type second-hand filing cabinet.
Drill vent holes on the sides and back at the top of the panels.
Into each drawer bottoms, drill a large number of holes. A dozen or more should do it.
Place a disposable foil baking tray in the bottom drawer, fill with BBQ charcoal and light.
Depending on what you want to cook/smoke, the hotter you need it, the lower the drawer you should use. Always put cheese in the top drawer with a small fire.
Remember this is a slow cook but a four-drawer can cater a good sized party given enough time.
The was the meal cooked tonight. Well the beans, corn and gravy weren't. Always refer to a range of online instructions for making these to ensure you don't accidentally poison yourself.