I found THIS site, the program works well

I love creating big beautiful oil paintings! At the moment, my artworks of fruits, vegetables and other objects are small because I'm producing them for a daily painter's website, but I'd love to make a large one for the fun of it. Honestly, I love seeing ordinary objects - like pears, apple wedges, lemon slices - close-up and huge. Let me know if you'd like to create some artwork together.

Hit your local travel agents and see if they're throwing out any posters - especially (as far as my own tastes go) for oriental travel.

Or do the same with local theatres or cinemas - most travelling companies, drama, dance, whatever, take their posters on from place to place, but there are occasionally some left behind.  Or any other establishment you can think of that uses large posters for advertising or PR - even video rental shops often have the odd poster to spare.

In any of those places it's even better if you're a regular, of course.

Here's an idea... that I have done already (photo will follow).

Paint your wall in a matt colour

Choose a cool 2 dimensional design you like (I did a Yin/Yang symbol with thicker outer lines).

Paint the design on your wall with GLOSS paint of exactly the same colour..

This gives a really cool effect especially at night...that is subtle and a great conversation piece...

BUT

Be aware if you ever want to move out of a rental apartment or change the design you will have a problem as it's quite difficult to get the gloss paint off the wall !! Only solution is another design on top or wallpaper !

I've picked up natural, handmade papers at farmers markets or other local community stores. They are pretty large pieces, thick, and worked well on my wall. I actually hung one on the wall, using very small nails in the top corners. In the past, I found lovely, bright sarongs at the local thrift/consignment and hung them up!

Another idea we are playing with for our condo (which has massive wall space) is to hang a curtain rod up on the wall and drape a delightful sheer and modern curtains. It gives a room the feel like there is a window or an open-ness that might not acually exist.

At work, we  mounted a rod from the ceiling and hungo plain, thick curtains to create a backdrop for our lobby. It also acts as a divider. Would be a good idea if you need to create some space or divide two rooms with no wall. 

Let us not forget thrift stores! I have found some large art pieces there for nearly nothing. I paid about ten dollars for a rather large, but unattractive landscape painting at a yard sale too. I simply painted right over it. At another second hand store, I found a beautiful batik piece that appears old, and as though it has been around a lot, it was in a frame. I paid four dollars for that, and it went up as is. 

So, scour the thrift stores such as salvation army, volunteers of america, or whatever may be local to you.  

Of course you could always hang a vintage rug or blanket, adding a rustic warm feel. 

You could do a mural on the wall or onto canvas.  Rent or borrow a projector from your local school or library. Find an image you like a just trace and fill in with your medium of choice.  Seal if necessary. This is as easy as a coloring book!

You could layer/decoupage sheet music, magazine clippings, etc for a modern look.  For a nice touch, do a solid outline of a particular object on top.  for example, ontop of asian writings in the background, place a babboo shapes ontop in a solid color to make it pop.

You could use left over CPU parts and create a modern piece by just gluing or screwing them onto a painted piece of plywood cut to size.

You can also hang up collections of things you like, either on shelves or in frames or directly on the wall.

For example, we are going to hang my boyfriend's guitar collection on the walls of the dining room (it will be a "rock and roll" theme). They are colorful and I think they're going to look great. Then we can choose a rug and other accessories (vases, etc.) that will accent the colors of the guitars. We are going to paint the walls first, because I think it will really add a lot to have color on the walls. I will post a picture on my profile when we are done (this could take months -- don't sit around waiting!).

You could do the same thing with any number of things -- vintage plates, wind-up toys, folk art statues, a quilt -- whatever you're into.