A number  of frames hold [39 gallon leaf-litter] bags. These frames are in turn held by table-like bases which can easily be stacked. I wouldn't trust the bags to hold anything very heavy, like glass or paper products, but for plastics, it'll be great.
Total wood use , excluding prototyping, was 14 eight-foot (3x1 nominal, I think) furring strips and about 50" of 2x4 - about 25$.
I also used about about 250 1.25" staples and maybe 6-8 oz of wood glue, though you could get away with somewhat less of both.
As far as tools go, you'll need a radial arm saw (or suitable substitute), some way to rip a few furring strips in half (a table saw or band saw with a fence would be ideal), and a brad or staple gun.
Total build time, excluding design, prototyping, and rework, was about 5 hours - about two hours of cutting and three hours of assembly.
I'm providing a [pro/ENGINEER 5] parametric sketch so that you can modify the design to make it in different sizes, or for slightly different uses, like lightweight tables. (at this time, I can't figure out how to attach files, so I'm hosting it here