Cost for Ridgevent and Soffit installed?

I recently had a family member come help remove mold from an attic and is almost at the step of putting ridgevents in my attic and soffits so the roof will be properly ventilated.

What is the average cost to do so on a cape cod style home?

Currently there is no ridgevent and where the soffit is is covered by wood.

$7-10 per foot for ridgevent is common around here.