Plywood?

[bigshrimpin]

I've use doug fir marine plywood a/b. It's about $50 for a sheet of 1/2 and $65 for a sheet of 3/4. Also if you can find MDO (what's used for billboard signs) that is a little less and very good quality usually no voids (comes with 1 or two paper faces).

Sometimes you can find a sign supply shop that will sell you old bill boards for $10 a sheet 4/8 3/4" MDO. I bought 15 sheets from a place at $5 each to do shelves for a friends garage.