$300 sounds right... shipping is negligible so 3 times that in the US... around $1000 would be about right. The other $8000 is just for the brand.
Given maybe $500-800 in production cost, shipping, duties etc, the cost is probably $1k. It is significantly more expensive than other fibers.
1. https://www.archibaldlondon.com/us/collection?category=vicun...