Before the summer update 2005, coconuts were very rare as they were only dropped by Demons. Since they are now dropped by Sibangs instead, they have drastically dropped in value. Putting a Blood Herb over 10 Coconuts will make a very nice decoration background.
This item was once only lootable from Demons. Therefore, they used to have a price range of 2,000 - 8,000 gp each. After Sibangs were introduced they became much easier to obtain, and go for a price of anywhere from nothing at all to 3 gp each.