High Numista rarity index doesn't mean more than there are few Numista members wishing to offer this coin for a swap.
Nevertheless, if you have this coin dated 1841 or 1842 in F - VF or higher grade, it should be worth more or much more than 1 euro.
I collect coins and tokens which circulated in Africa from 18th century to 2000. I sell about 7000 illustrated world coins from http://www.avscoins.com.