just one bunker for a back garden, looking to spend around £35 to £40
Heres a tip!
Get a cheap car cover (Not the micropourus breathable type) just a bog ordinary weatherproof one like they sell in Lidl from time to time for under £10
sew up the open bit to create a bag. get a stiff bit of vinyl or pvc and a large CPU fan (From a computer) wrap the pvc around the cpu fan glue it up to form a tube with the cpu fan down one end. cut a hole in your car cover at whats going to be the base then sew/stick tie or tape the cpu fan into the hole with the tube of pvc sticking out. shove the cpu fan onto a bike battery and badabing a bunker will appear as if by magic! (as long as you made sure the fan was blowing into the bag and not sucking!)
Whole thing should cost under a tenner and be fun to make!
This is not a windup.......it really does work, I have made bunkers this way!
Now take some sticky black plastic and a toilet roll..............
Failing that, get one of cliffs!