One of my favorite spots is the Flower Bridge in Simsbury, CT (a walking bridge). The bridge is maintained by local gardeners and when the flowers are in bloom it is a gorgeous site, right on the Farmington River. If you plan an outdoor wedding, always have a plan b for the ceremony.
I think maybe $50 but the town of Simsbury sets the fees so they could change from year to year due to budgets. Best to check on fees and any rules they might have that govern usage...are you getting married? I don't come with the bridge fee!!