I have used the stuff for years and have a number of patterns that use quite a bit of it. Last week in Bangkok at a China Town market I found "sorta" bulk rolls of it being sold for making bead bracelets. It is Spandex and when cut under tension the ends "explode" a little bit and ravel. A bit more so than actual branded "Flexi-Floss."

They came in packs of 25 spools in 13 colors, 2 of 12 colors and one different, they varied a tiny bit. Each spool was about equal to 3 to 4 packs of FF. Worked out to $.29 per spool. I bought three packs of 25 and am already wishing I had gotten more!