Anyone know the best place to buy plastic sheet?

[bjb]

I have a couple aquaria to cover.  I'd like to find some plastic sheet, perhaps 1/8" to 3/16" thick.
I read MadMatt's post showing corrugated plastic.  Very economical, but I'd like to purchase some flat sheet.
I figure it won't be nearly as cost effective, but I've only got a couple tanks and the covers should last indefinitely.
I've seen some on line, but wow, it's expensive.
Polycarbonate would be preferable over acrylic.
Just hoping one of you had an idea where to find the best price on this stuff.

Thanks

[Andre]

Lowes sells small sheet of glass and it's not too expensive.
I think they will cut it for you as well..

[freshwater]

I have tryed clear plastic or acrylic lids on a few diferent tanks over the years and even on smaller tanks the plastic always warps and sags in the middle, I would have to keep flipping the lids over about every week to keep them somewhat flat and that was 3/16 thick. I have seen Matts lids and I think that is why it works because it is corrugated to keep it ridgid. I have changed all my lids to glass

[gabor129]

I think they sell polycarbonate sheets too.

[lesfromlakeshore]

I ordered some acrylic lids about 5 years ago from a seller in the States who I think is no longer in business . While the lids on the small tanks work well ( 5.5 and 2.5 gallon ) the one one the 30 gallon tends to warp the the middle like Keith says .