i was riding my bike, and noticed a clicking sound. one of the little spinners in my derailleur broke off right outside my house (i found it walking home). i went down my half mile hill and about another half mile before my bike stopped working, pedals had no resistance. the chain was also REALLY loose. some guy came outside his house, saw me struggling, and told me what was up. i decided to get a new derailleur since it looks all buss-up anyways. i had a shimano, so im looking for shimanos on ebay and i will look into my local bike shop. any recommendations on what to do?