Huge difference in price of liners online vs a brick and mortar store. The marble that is currently rolling around my head is telling me the big difference in liners is the gage or mil thickness of the material (I know gauge and mil are two different animals). And I am looking for overlap type.

Is there a piece of this puzzle I am overlooking?

Also some liners allow for the center to be deeper. I guess they have additional stretch built in. Any information about that?