Yeah, so there's the DOH, and then there's Hmmm...
With DOH, you're getting a killer deal if you don't care about color.
With Hmmm... you're getting a killer deal if you don't mind some deficiencies in the filament strand. You see, making Purple Reign is pretty tough; we only use raw pigment (as opposed to master batch) with this color, so keeping a consistent flow of recycled plastic is really challenging. SO, either there's variations outside of +/- .05 (and barely so) or the diameter is fine, and the filament snapped during the extrusion process, so we wound a second filament onto the spool.
For $13, we think you're getting a sharp deal. Hope you feel the same!