It costs 3.99 US Dollar in the US, whereas here in Germany, Ikea Cologne is charging 5.99 Euro. The bag`s measures are: Length: 65 cm, width: 22 cm, height 65 cm.
The transparent bag is made of sturdy plastic material, polypropylen. It comes with zippers that make it easy to pack the Brompton.
So far I have been really satisfied with it.
Kris Ablan in the Philippines has a nice illustrated report about his packing experience on his blog "Riding a folding bike around Manila".