For a single person, I rate this kind of thing:
http://www.militarymart.co.uk//british-army-issue-camp-bed/prod_380.html
Plus points:
It packs down reasonably well - Not much bigger than a rolled up (& slightly pointy) blanket.
The sprung steel legs and frame mean that it supports you nicely. I have get you find another camp bed as comfy.
Awesome value for money. You can spend a lot more money and end up with a much worse bed.
There is a trick to putting them up - use your body weight to put the legs in. Don't try and just squeeze them. Locate one side of the leg in the frame, then put it on the ground and lean downwards on the other end of the leg to compress it. It should then slide into it's locating point reasonably easily.
Downsides:
Not idiot proof. Everything does have to be properly located to stop them falling apart in the middle of the night, and as mentioned above there is a bit of a trick to assembly.
Because of the shape of the legs, if you put all your weight on one side of the bed then then can roll over and dump you on the ground.
