I would think it would be pretty easy to DIY the plain banner. All you would need would be the fabric - what ever type you go with and some wooden dowels from a hardware store to attach to the bottom and top.
I'm DIY-ing mine. I don't have a picture up yet. But I bought Ivory Satin fabric from JoAnn's! I painted the letters with a bronze paint that has a little tiny shimmer to it! I bought a small 4 dollar cafe rod from Target. I'll post pics once mine is done! You can use any fabric that doesn't bleed the paint or whatever. Really pretty fail proof DIY! Good luck!
All you would need would be the fabric - what ever type you go with and some wooden dowels from a hardware store to attach to the bottom and top.