How much did the bar of gold that Achan took from Jericho weigh?

Answer: Fifty shekels

Achan took a beautiful cloak, 200 shekels of silver, and a bar of gold weighing fifty shekels (KJV: "a wedge of gold of fifty shekels").

“When I saw among the spoils a beautiful cloak from Shinar, two hundred shekels of silver, and a bar of gold weighing fifty shekels, I coveted them and took them. They are hidden in the ground inside my tent, with the silver underneath.””— Joshua 7:21 (BSB)