That's a blanket statement that isn't true for everyone. For example, in my home, we're gluten free, because of me, and dairy free because of my husband. Not by preference, but because of actual medical conditions. And gluten free flour is about 8 dollars for a tiny bag. Rice might be cheap, but what rice, plain old parboiled white rice? We don't know the OP's diet restrictions. It might not be that easy or that cheap.