Save space by using this hack. It's simple and easy. Instead off having three beds next to each other or having a bunk bed with another bed taking up valuable space, you should use this idea.
Step 1: The Bunk Bed
Make sure to get the perfect bunk bed. The bottom bunk should have a little more then a foot gap under the bed.
Step 2: The Mattress
Get any kind of mattress as long as it is about 6 inches tall and can fit under the bunk bed. Tuck mattress under bunk bed during the day and pull out for the night.