One 2x12x8 will make 40 top and bottom bars. A few more if none are ruined due to knots, a few less if there are a LOT of knots...
so thats .31 cents for one top bar and bottom bar.
One 2x12x8 will make 15 blocks to cut end bars from. Each block will make approximately 17 plates or side bars. So around 255 side bars per board = about 5 cents each. So that comes to around .36 cents, minus blades, router bit, electricity and thumbs.. oops, did I say thumbs?