This page explains how to start and complete the The Priceless Maracas side quest.
How to Start the Quest
Go north from the Dueling Peaks stable (near Ha Dahamar Shrine) and cross the Kakariko Bridge, then continue along the road and you will find a large Korok, named Hestu, next to a tree. Talk to Hestu to start the quest.
How to Recover the Maracas
The Bokoblins are to the north, through an archway in the stone. You may find it easier to climb up the nearby wall to shoot at the Bokoblins from above. After you defeat all the Bokoblins, the nearby treasure chest will unlock. Open it to get the maracas.
Return the Maracas
Go back and talk to Hestu to return the maracas. If you have found any Korok Seeds, you can give one to Hestu, who will offer to expand your weapon stash, bow stash, or shield stash. Thereafter, you can talk to Hestu and exchange Korok Seeds for more stash expansions.