Hello, Brunin!
It is quite hard to esteem the value of such kind of items, since they are really rare and can't be sold on market.
For coincidence, today a brazilian youtuber served as a broker for a Banor doll. It was sold for 40k TC.
You can see here the whole video.
But please take in account that this does not mean that is the correct value of the item. It may vary depending on how many people wanna sell it and how many people wanna buy it.