By Mauricio Alencar What is an FA Cup run worth in prize money, TV fees and other income to Newport County, who meet Manchester United in a David-versus-Goliath tie this weekend? City A.M. does the sums. For League Two football clubs straddling the edge of insolvency, playing a sell-out FA Cup tie against a Premier League giant is a rare lifeline for club finances. Newport County are set to host Manchester United on Sunday, when – regardless of the result – significant income from the competition’s prize fund and live broadcast on BBC One will boost the club’s hopes of avoiding further losses …