The Ancient of Youth, Quincy, was released from the Bazaar previous to the storm ancient, and cost 100* baubles. With the increase of at most 10 baubles for each month it's been out of the bazaar, I'd say maybe 155 baubles, give or take.
Hello! I'm locking this topic because we've got some threads for this already- if your pets are already in a trade check out the Is This A Fair Trade? thread and if you just want the average value of one of them you can check out the What's This Pet Worth In Baubles? thread~