Do it your self for free nest boxes
First you will need
a large drill bitt, 3 screws, a drill, a saw, a five gallon bucket, and some wood.

next you will need to cut your wood to fight the bucket you want it to cover 1/3 of the opening of the bucket.

then you will screw the bucket down to the board.

next you need to cut the remaining screw off with a saw. I used a saws all with a metal blade)

then you will need to drill holes with the drill and drill bit for ventilation.

and the finished product