I made some simple ones by cutting the top 1/4 or so off a plastic soda bottle or jug [any size], flipping the top upside down to make a funnel that goes down into the rest of the bottle. Duct tape the edges and put in 1/2 cider vinegar, 1/2 water and a few drops of dish soap. I've caught hundreds of yellow jackets at my hives in just a few days.