I was thinking of buying a rain barrel when I found two tree size planting pots next to our dumpster. They both had rims about an inch wide, so I set one on the ground right side up and put the other one on top, upside down, then used small bolts to fasten them together. Then I cut out the top and lined it with a very heavy plastic bag, taping it at the top. Also made a plywood cover for it, with a screened over a hole for the water to enter from the downspout. I like being resourceful and using found free stuff and still getting the job done. I don't know how many gallons it holds, probably only about 40 gallons. I dip the water out of the top with two 1-gallon jugs. It's fun.