Want low-cost furniture for one-off events, like trade shows, exhibits and fairs? Sure, you can drive by the salvage yard trying to score the cheapest crap you can find. Still, I doubt that's going to prove any more affordable or more convenient than Zona Uno's cardboard elements.
Geared towards showrooms and events, they offer a varied selection of cardboard furnishings specifically for those purposes. Currently available items include different types of tables (inclined, flat), poster panels, computer display panels, various sizes of stools and trash cans.
Each set is made from Vulcano microwave cardboard, a light but sturdy material that can be easily printed on. They all ship as flat boards, with complete instructions on how to fold into the utilitarian pieces. All items come in specific sizes, so if you have very particular needs (like a giant poster board), they probably wouldn't be able to supply.
According to Zona Uno, all the tables and panels should be able to handle a good amount of weight, so it's safe to have people occasionally lean on them as well as put regular showroom stuff, like computers. The intent seems to be for the furniture to be disposable (European disposal taxes are included in the purchase price), which sucks, since I can probably haul stuff like this for an entire year's worth of uses. Most of the pieces will need to be glued to hold sturdily, so you can't fold it back out for easy transport later.
Regardless, I'm very enamored with the designs. It's practical, convenient and, at costs ranging from between €25 to €85, extremely affordable. Not sure if they deliver in the States, but it looks worth the try.