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.