Pricing a Birdnest colony

This may not be a common question here but i am having a hard time determining this.... I have 2 large pink birdnest colonies. I have been considering selling one of them to make some room and a few bucks toward a new build i am doing. The colony i am looking to sell is almost the size of a basketball. it really is hugh. I have no idea how i should price it???? i tried looking for other colonies others have sold like it but i havent found any close to the size of this. What do you think???