Not having much money but wanting a pond, I bought a reused vinyl tarp, a big one.[ Way too big for my pond, but anyway: I have already found another use for it. When I first got it, it was a bit cold, and I was afraid I would have trouble installing it. It was heavy and I feared I would have trouble.
The secret is to unfold it during a sunshiny day. [Boy I wish I could use bold face type and underline that!]
It took me a while but I managed to lay it over the hole for the pond all by myself. Making sure it wasn't overstretched, I then started filling up the pond, stopping to rearrange the folds.
Now, I just have to add a wooden border that I can **** on the wood edge and fill it up all the way. [I used telephone poles that my town was getting rid of.]
My pond is only 10 X 20, so I did have a lot of tarp that didn't get used. But that's OK: I will make small shelters for my younger chickens.