Because this model of reel is relatively inexpensive it doesn't look as if these are items that are sold routinely by dealers. Therefore you will probably need to buy a second hand one. That doesn't mean it's an impossible task. I get all my spare spools off eBay. A lot of them are second hand (but after all, a spool is a spool)! I've just had a look and can't find any on sale there at the moment, but if you keep an eye out I'm sure you'll track one down sooner or later.