I used wool roving from 21st Century Yarns in Black and Delphinium. To prepare them first you'll need to roll them between your palms, then either knot the ends or press them with a hair straightener.
You can do this as one big one or two smaller ones, but I think two is easier because then you have the choice to wear them as two over bunches, or put them both over a ponytail.
Sort out your bits of wool. You'll need to work out how long you want them to be, then double that and cut them to that length. I only realised that'd be easier after cutting all the blue ones though. Put them in two piles with whatever other bits you want in them (I have some bits of decorative wool). Cut some elastic to a length that will fit over a bunch of half your hair.
Sew the bits of wool onto the elastic. I just used normal needle and thread and it worked well.
Done! Now that wasn't very hard at all. No point paying Â£30 for something you can make yourself in ten minutes.
Wear your dreads with pride! Probably in a higher ponytail than this though