Buyers typically pay for fiber laying by combining material costs, labor time, and permitting plus trenching or aerial support fees. Total Project Costs: For commercial installations, expect costs ranging from $5,000 to $20,000 per mile for underground projects and from $40,000 to $60,000 per. Buying fiber optic installation services involves several cost components, with total price influenced by length, location, and access. This guide breaks down everything you need to know before starting your fiber installation project. Quick. These networks are constructed both underground and through aerial fiber, at an average cost of $1,000 to $1,250 per residential household passed or $60,000 to $80,000 per mile.