I found a pattern for a booster seat that I want to make for my DD. I got all the materials but the 3lbs of Buckwheat Hulls. I am assuming I can only order them online as I looked at JoAnn's and Hobby Lobby's website and they don't list them. Is there a place that is better priced than another? I found a 5lb bag on Amazon for $30, which I guess is not too bad. Anyone used any before? Is there a cheaper substitute?