He didn't have enough change to buy a pack of tissues, so Peoria police say a man came back to the store and robbed it.  The Peoria Journal Star reports that police are looking for a suspect who they say held a gun to a clerk's head at the Family Dollar store and took cash.  Investigators say the robbery began when the suspect tried to buy a pack of tissues.  He came back about ten minutes after being turned away, and pulled his gun.  Police say no one was hurt, they have a description of the suspect and are looking for him.