RepairPal Certified shops can diagnose and repair your 1995 Chevrolet Lumina. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
$140 is about right. the labor is around 1/2 an hour and the tensioner is about $90. This not a terribly hard job, but I would make sure you have a good diagram for the belt routing.