I think there is an official help thread..meh.
Go to Zora's river, and follow the path up to the boulders (you must bob, if this is your first time) and just talk to the man eating, he sells you beans for 10, 20, 30, 40, 50, 60, 70 ,80, and 90 rupess, after which, he sells out!
Hope this helps
