Step 1: Material
1 Wooden board in the same dimension I wanted my desk in.
2 Offset boards. Usually 93 x 56 cm. These you can get for free. Just call the printer of newspapers in your town and ask for Offset boards they can't use because of misprint.
2 Brackets to fasten the desk to the wall. I didnt have any good material to make mine of so I bought mine at ikea. Therefore the cost of $24.
1 Pair of scissors, Old ones that you can dedicate to cutting metal.
1 Box of glue to fasten the aluminium boards to the wood. $5, It has to be a bit elastic because wood is a living material that expandes and shrinks with temperature and moisture in the air.
1 Saw to cut the wood
Some screws to fasten it to the wall and the desk to the consoles.
A ruler and a pencil.
Step 2: The Desktop
Then put the wooden board on the backside of the aluuminium (offset) board and trace the sides of the wooden with a pencil. Now remove the wooden board.
Take your scissors and cut of in the corners so you can fold the aluminium around the wooden board.
Apply glue and replace the wooden board within the traced lines.
Then fold the parts of aluminium around the wooden board to cover the sides.
Now your finished with the desktop. Let the glue dry.