Our Lowes had the BOSS accessory kit on clearance. Normally in the $60's.. reduced to $10. I already had one that I paid full price for years ago, but for $10, it's almost worth it just for the sandpaper. .. but it has the 6 spools, and plates for each spool, as well as the organizing trays that fit in the BOSS.
If you want to have some backups for spools, it's a good deal. Of course, maybe it's only my location.