Set your Ryo to 99,999,999 after any battle or shop transaction.
This article provides a fully updated, verified, and safe list of cheat codes using the method. Disclaimer: Modifying your Wii requires a softmod. Proceed at your own risk. Sengoku Basara 3 Utage Wii Cheat Codes UPD
Gain 9,999,999 gold (Koban) after completing one stage. You can now buy all weapon upgrades and shop items. Set your Ryo to 99,999,999 after any battle