Never built one but that one looks simple. Take a 55gal drum, cut a hole in the bottom. Take a toilet mounting flange for either 3 or 4" PVC. Insert flange from inside and you could screw thru the drum to secure it. Use a series of T's or Y's in the plastic along with 90's or whatever configuration you want for the discharge. Not sure how they do timers and such but that looks like what I have described in the picture except with fancy molded plastic and marketing. Like I said, I have never built one but it doesn't look difficult. Just throw some Redneck ingenuity into and you will be golden Corey.