Agar agar= ballpark

“How much is that diamond ring?” asked Tai Tai A.
Tai Tai B shrugged, flashed the glistening stone in front of her friends, blinding her friends.
“Come on, give me an estimate, agar agar,” Tai Tai A persisted.

What Tai Tai A could have also said:
“Come on, give me a ballpark figure.”

Ballpark refers to the stadium in which ball games are played but it also means a range which an estimate is likely to be correct.

For example:
-I don’t need to know your exact salary. A ballpark figure will do.
-Please try harder, your guess on her total wealth isn’t even in the ballpark