Consider using inexpensive materials such as washi tape, posters, or framed prints to decorate your walls on a budget. You can also make your own art with items you already have around the house, such as old magazines, scrapbook paper, or fabric. Another option is to use removable wallpaper or decals, which are less expensive than traditional wallpaper or paint. Creating a gallery wall with photos or artwork can also be a stylish and cost-effective way to decorate your walls.