Slab Poured

Placed a brace on top a sawhorse to support the middle of the Wonderboard. Then poured concrete over the rebars.

Sloped the sides up nicely ---no wood forms used or needed (saved some money):

Spent more money on cement and sand.

City Mill:
Sand, 7 each @$6.99
Cement 94# @$16.27
Wooden Dowel 1 5/16 x 8 feet (for leveling insulation cement) @ $11.49
Total: $80.31