A Doylestown man has been sentenced to life in prison for killing another man last May.  31-year old Zachary Becker was sentenced yesterday in Stark County Common Pleas Court after being found guilty on counts of murder, felonious assault and tampering with evidence.  Authorities say Becker had gone to Stark County to sell a gun, but that something went wrong and he ended up fatally shooting the buyer, 38-year old Michael Gates, of Canton.  Becker, who will need to serve 21 years before being eligible for parole, is expected to appeal his conviction.