We have a large wall that runs the length of our living room that was just begging for something to fill it. Big pieces can get pricey, though, so I got creative.
I printed a favorite photo that I took myself in the Colorado mountains and printed a 20x30 poster size of it at Costco for only $9.99. Next, I found a frame for the print at Ikea for $19.99. I had thought about doing 2 or 3 of the framed photos, but I came across the wall decals. I like how they add to the "footprint" on the wall but at a more reasonable price than 2 more photos would have cost. The decals were on clearance, because they were being discontinued. If I remember right, I paid around $10.
So, with the cost of the decals I filled the wall for a grand total of about $40-50. Not bad!