There's a dozen ways do it, but the hot tip for the bench top is Menards sells pre-cut 2ft x 8ft ACX plywood, that's already sanded on one side fairly good. A little finish sanding and top with polyurethane and your good to go.
I've done it with 2 slabs of plywood expoxyed together, it's solid as all get out.....
Cheers and beers...