Have you heard of www.freevintageposters.com?  It is a great source for free artwork.  You could take an image from the website to a printer and have a high quality poster made in virtually any size!  There are ten different categories to browse through and many images to choose from under each heading. 

I liked these two botanical posters for the colours and their simple, graphic quality:

I thought these two would be sweet in a little girl's room:

This one would be perfect in a kitchen or dining room:

And the two travel posters might be fun in an office or den:

In my next post I will discuss another source for cheap, cool art!