It depends on the financing and rate structure. If property owners pool their money to fund the project, the per investor cost will vary. If a millage is approved, the cost will be determined by taxable property value, reflected in the rate structure, the length of the millage and the interest rate on the bond to be paid off.
In Lyndon Township (2020), a resident can choose from 3 unlimited fiber internet plans; ranging from 25 Mbps @ $34.95/month to 1 Gps @ $69.95/month. http://www.lyndonbroadband.org/faq/# + millage
In Sharon Township (2017), it was estimated that the monthly cost for the average property owner ($77,000 taxable value) would be under $100 ($35 for unlimited high-speed broadband plus approximately $45 per month for the millage.)