I wouldn't buy a used helmet. A brand new HJC at half the price will protect your head more than that lid if it has been dropped, and there is no way to tell (besides getting it x-rayed, but when that is done, you are probably at the cost of a new lid). Getting your head smashed in is not something a doctor can usually fix, one chance only. Is your head only worth whatever the price difference is between used and new?