Storage rings are pretty commonplace in the Cultivation World; any slightly larger sect would ensure that each of their disciples has one in hand.
However, in the End of Dharma Age on Earth where cultivation is in decline, these items are rarer than phoenix feathers and unicorn horns. Despite their unimpressive appearance, which could even be described as ugly, their actual value surpasses that of diamonds and gold by tens to hundreds of times. Plus, they're not easily available for purchase; having money doesn't guarantee you can acquire this treasure.
"The auction for the Black Stone Ring starts now, with a starting bid of fifty million, and each subsequent bid should be no less than five million. Please bid!"
"Fifty-five million!"
The auctioneer had barely finished speaking when someone bid fifty-five million.
"Sixty million!"
"Seventy million!"
"One billion!"
