We salvaged four hardboard plates covered with a white finish from an old closet.
Then we got cover-foil to protect books for a total of € 10,-
We had enough screws lying around so those where free also.
In total we used 21 screws and one washer
The tools we used where a measuring tape, a knife, a wooden spatula and a drill with screwbit.
Step 1: Basics
Be sure to clean the surface you use for the plastic, because every hair shows up on the finished board.
Step 2: Align plastic
Start at the bottom so every layer above the bottom one overlaps the previous.
Tape the foil with the paper side down using the grid on the backside to the desired amount of overlap. After taping it down make sure the vertical lines are in line with the side of the edge of the surface and tape down the top half.
Step 3: Apply foil
Use a wooden spoon or another non-sharp surface to push out the air beneath the foil.
Start at the inside and work your way up and out. Like so: