I used a 20x100 ft plastic liner that I got from home depot. I used silicone
and duck tape to seam it together. There was some leakage but it was cold enough so it wasn't much of a problem. 

Too my dismay I found out how unlevel my backyard really was after I started to fill the rink. I had to use 2x8 ft sheets of plywood along the back to build it up enough so I would have ice in the front. There is 15 inches of
ice on one end and 3 inches on the other.

After it was all said and done, it cost me about 175.00 US. I now have a
great skating rink for my three daughters ages 2, 5 and 16.

Hopefully the cold weather will hold out here in the great state of New
Hampshire for a couple more months.  Thanks for all the great tips I received on your website."

Great job and thanks for the pic Rick.