Cheap, temporary raised beds.

So I'm living in a place I don't intend to stay and trying to build a bed on an exceptionally tight budget (I have maybe $20 in spending cash every 2 weeks).
I want to make my bed temporary and cheap so I was considering, rather than buying wood, perhaps building it from cheap landscape cloth and a wooden frame. Has anyone seen anything or tried anything like this?
I was going to build a box structure from scraps of wood about 1x1", probably with posts every 2' and then staple the fabric on 5 sides (leaving the top open obviously). I don't know if this would be sturdy enough for a 8'x2'x1' structure (or maybe 2 4' long boxes). I could also reinforce it with a wire mesh like chicken wire. I'd look into getting scrap wood to build with but I don't have the tools to cut large pieces of wood.
As an aside, I'm building said bed on concrete. I've read this requires a layer of stones at the bottom for drainage but I read elsewhere that fabric on the bottom was fine. Any thoughts on that perhaps?
Any ideas or advice are very much appreciated.

Okay, this is going to sound crazy...

I live in a city where there are constantly free entertainment units and bookshelves at the side of the road. Computer desks too. There is an especially good harvest of used cheap furniture whenever university term ends. Seeing these unwanted goodies I thought to myself, if I put that bookshelf on it's back, filled it with compost and top soil, I would have an instant raised bed. I haven't had a chance to try it. I think it would only last about one growing season, and the mucky stuff it's made from might leach into the soil (if that concerns you), but for an instant, temporary, raised bed, I bet this would work.

Another free resorse are pallets. These are the wooden shipping things that the forklift uses. One needs a crow bar and hammer, then one has free wood. One takes wood, builds hugelkultur bed.

Both ideas make sense. I get weary of roadside furniture if only because OH has such a ridiculous bed bug problem. I did see free pallets on Craigslist though.