I built myself a twin bed once. Not sure if it would work well for children if they were rambunctious. I used 4 overturned 5-gallon buckets. I put atop them an iron bedspring that a neighbor gave me. I put the mattress on top of that. I put a dust ruffle under the mattress and it was just the right size to cover the buckets. It made a comfortable and functional bed with storage underneath. ... View related article.