Who said "I've learned that friendship is more valuable than gold."?

This quote is attributed to Theon Greyjoy.

I've learned that friendship is more valuable than gold. - Theon Greyjoy

"I've learned that friendship is more valuable than gold."

Theon Greyjoy Friendship

"I am the Prince of Winterfell. I have no need to prove myself to anyone."

"What is dead may never die."

"You can't marry her. You're promised to me."

"I'm a Greyjoy. We do not sow."

"Friendship is built on trust and honesty."

"True friendship is worth more than gold."

"Good friends are like stars, always there even when you can't see them."

"Friendship means sacrifice."