I don't know if you can buy or get second hand bands to work. But you can buy bands at the Disney Store. They also have more elaborate bands inside the park.
http://www.disneystore.com/disney-parks-magicband-red/mp/1363805/1000387/
So if you don't have Magicbands, you can't get any FPs at WDW? If so, that stinks...
No, as was stated, Magic Bands are a convenience, but not a necessity. If you're staying off property and don't want to buy a Magic Band, you just use your ticket at the FP readers.
Wait, so you can get FPs if you don't have a magic band then? I was under the impression that if you didn't have a magic band, FPs were out of the picture for you and all you could do was stand-by. Do you still get paper FP tickets (or I guess WDW people call them Legacy FPs) if you don't have a MB?