Call Bend Tarp and Liner. I shopped around alot! They have a thin liner that is very cost efective and very very tough. I had clean dirt with a few small pebbles. Your soil will determine if you can use the thin stuff. I tested a piece of it by running it over with a bobcat before I ordered. It will be roughly about the same cost as the plastic you talk about. My liner was 165ft by 295ft. Came in one piece and was worth every penny. I put about a foot of dirt on top of it. Its now full and looks great. I fought leaks for a long time.
