Tx, I'm guessing that you have about 50ft of ridge vent and that should run about $9.00 a ft for labor and materials on a walkable pitch. Intake vent for the soffit leaves about 450.00. It's not out of line depending on what they are installing, how high is the soffit? What kind of access? It doesn't sound out of line. Not a brother-in-law deal or a felony hold-up.
Pics would help.