I like TreeBird's floss. They have silk and bamboo/charcoal kinds. They are very affordable, IMO. I buy their bamboo/charcoal refill pack for $18 and it lasts me a long time. I floss everyday and I use excessive yardage of floss, yet still it lasts a long time. Their containers are cool (glass and steel). Strongly recommend it.

https://treebirdeco.com/collections/floss