Puzzle Bed 

I made this bed that is strong, stable and inexpensive and has no hardware.
As is tradition on Reddit, the finished product

The posts are approximately 6″x6″ and are very sturdy

 The sides slot together and meet in the middle, no hardware.

Just for fun, the cat’s eye view (under the bed)

Breaks down to a compact pile of lumber that could perhaps be put into some sort of bag, perhaps.
Here are the parts in separate piles:

The posts

The sides and ends

The slats

Midline support

This is made of the following materials

4 2x8x8′

3 2x6x8′

6 1x4x10′