The two containers shown are freebies- the large one is a 200lb Cow Lick Tub bought from Feed stores most farmers throw them away. They are probably 30-35 gallon size, hang a sign at your local farm and ranch supply store. The small one is about 3 gallon size and comes from the Flower dept at Krogers Grocery, Ralphs in some areas. They throw them away, my local store gets them in on Monday and Friday,
Both containers will hold water so if used for a plant make sure to drill lots of holes. I use a 1" spade bit, drill slowly, the smaller bucket will break. Both have Carbon Black for UV protection.