This is a great pattern for stash decreasing as the pattern calls for nine different worsted weight wool yarns. Figure one skein for the main color and make that color the darkest of the project - black, brown, dark purple, etc. The color on the bottom of the stripe and the bottom of the bag will only take around 20 yds or so. I don't have exact calculations on all the colors yet.
This bag can also be done in Noro Kureyon to great effect.