Just use milk crates (not the ones you buy at wal mart but the actual 4 gallon milk crates). Tie together with zip ties and if you wish you can spray paint or wrap in fabric for decoration. The fabric bins fit perfectly in them.
Milk Crate Boxspring--TUTORIAL - HOME SWEET HOME - My daughter moved 4 times in 4 years of college and we learned a lot about moving! For two years, she had a mattress in a loft bed, but that thing was