it definitely depends on the space you have to set up, whether you're working with one table or multiple tables, or a rack for clothing, etc.
Pinterest has been a great source for me for a lot of DIY display ideas, without having to spend too much money. You'll want your display & any props to compliment what you sell, whether it's a color scheme or theme to go with your products.
For headbands, I've seen sellers at fairs use glass/acrylic vases (wide cylinders, like hurricanes) or PVC pipe covered in fabric to stack headbands in one place.