Curtains and decor pillows can be a lot of money. Depending on the fabric of a curtain you want and your window's size, you could spend more than $100 for curtains for just one window. If you can sew a straight line, you can make your own curtains. I made curtains for my baby's room to help keep it dark. I bought fabric at the hobby store when it was 40% off. Then, I pulled out my sewing machine that I bought for less than $100 10 years ago. I made my own curtains for his room for about $30.
If you find a pretty fabric at the hobby store, consider making a couch pillow or seat pillow out of it. Getting the couch or seat re-upholstered can be quite costly, but you can add a punch of color by adding a pillow instead. Use the pillows you already have and sew a pillow cover to slip over them.
You can find hundreds of videos on www.youtube.com on how to do these do-it-yourself projects.