i have seen them at lowes and home depot and they are nice but the best ones are made out of pond liner and stone they look more natural to me
just my 2 cents
You can also use a horse or animal trough, those rubbermaid kinds. they are very durable and strong. That's whats i'm planning to use as my little pond to keep Koi's.
Yah I have also seen them a lowes and home depot. I guess it depends on what you are keeping in it, cuse you might need a bigger one then what they sell? Anywho if you have prob with keeping it outside another thing i ve seen people do is by the mini green houses and pop them up over there ponds.