How to Make 'free' Brackets for Sturdy Shelves

I bought lumber yesterday to make the shelves themselves, for two 2"X12"X8' shelves it was $17.00, the brackets are made from end cut-offs from other projects...throw nothing away over 10" or so, you WILL find a use for the pieces if you have them around. I used scrap from a 1"X10" board for the outsides of the brackets, but you could use plywood or Blandex just as well. You can do variations by cutting the pieces for the outside ends fancy with a scroll saw or jig saw. Also, with the 2"X4" boards cut at 45 degrees you can add another side and 'front' piece to enclose the bracket. I used 2" and 3" star head screws, I had them leftover, about half a pound. I forgot to add, also not pictured, use the 3" screws to join the two 2"X4" boards together.  And I ALWAYS use Gorilla Glue now, it just can't be beat. It seems expensive but it is CHEAP for what it does. Spread a VERY thin coat on the wood surfaces before screwing them together.