A little art can really spruce up a room and add to the value of the decor. As art is subjective and since beauty is in the eye of the beholder, almost anything is fair game. Watercolors, oils, charcoal, digital prints, photography, etc. can all be used nicely to improve the look and theme of a space. So it stands to reason that you don’t need to spend a lot of money on interesting pieces.
As a note, I totally believe in supporting local artists, and if you should see something you like, help them out and buy it. But with that said, many people are working with tight budgets and spending hundreds of dollars on a piece may not be realistic. This is where you can get creative and find art on the cheap.
Garage sales are a great place. Most every one will have a framed piece. If you’re out for the weekend and pass one by, stop and take a look. You may just find the exact thing needed to complete a room.
Pawn shops (yes, your local ones like http://www.uspawnjewelry.com/#!faq/mu8qo) also sometimes have art. The pieces here will be a bit more expensive than at a yard sale or garage sale, but still much less expensive than buying from a gallery. You can often call in advance to see if they have anything before you make the trip (but hey, you may find some other interesting pieces while there anyways).
Lastly, don’t discount pieces that are “mass produced” like the stuff at ikea. Some of those pieces are really good and as we have seen before, it doesn’t matter how much it costs or who painted it for it to be a nice piece.