We bought this great J. Otto Seibold poster at Mass Moca and knew we'd never be able to actually afford a frame to go with it. The poster was $40 and the frame was something crazy like $400!
Just tacking up the poster with that silly putty stuff or thumb tacks didn't seem right. So, we decided that there must be a way to make a cheap, cool-looking "frame" for this gigantic poster.
threaded rod (1/4") X 2
paper binders X 10
nails X 10
We used 1/4" threaded rod because we feared that anything bigger would weight down the paper too much . So, we measured out the threaded rod so that it was about the same width as the poster and cut it with the hacksaw.
Next we just attached the binder clips to the rod (about 5 across), inserted the poster, and hung it on nails on the wall--like so:
We did the same for the bottom so that the poster wouldn't fly up everytime we walked through the room. At first I was worried that the whole thing would tumble down, but it's been a year and (knock on wood) it hasn't yet!
It's not as sophisticated as real frame, but I think this does the job and has a vaguely sleek look about it.